# How would you sand Acrylic DTM on steel handrails?



## ridesarize (Jun 19, 2012)

I'm working on a pretty big project here, working solo on it. I knew it was going to be a ton of work to complete this. It's pretty daunting, maybe a little overwhelming. 

Having to prep and paint this railing system with older acrylic DTM paint on it, which was the second product. There are many places where the paint is in good condition but maybe just a little bumpy, rough, or tiny cracks. There are places with small cracks throughout the surface and there are some places with a little more obvious paint cracks or flaking.
Sanding works, but not entirely effective. The main rail is the easiest to sand, especially with my new Festool LS 130. The smaller bars wouldn't be too terrible except for the fact that this is acrylic paint that doesn't sand well. It just blocks up, or balls up across the surface. I pretty much have to swipe my hand across the bars to remove the balled up paint as I sand, and change paper often. I'm using 180 grit which seems good. 120 is way too rough. I am not sure if festool's 240 would be any better but I would have to go buy some.

I'm using the dts400 to get a whole bunch of spots on the vertical tubes, and base plates (which are difficult to get surface contact on many that are recessed below the exposed aggregate patio.)

Hand sanding barely scratches the surface but is being done as a follow up to the machines and works at that point. 

What sanding tools or techniques would anyone recommend? Pneumatic? Paddle wheels, flapper discs, whatever, wire wheels, or even wet sanding?? I need a smooth surface and didn't think wire tools or grinders would be the way. Plus hard to contact the round surfaces, tight spots, and all next to glass panels.... this rail is at least 120 feet long. 33 posts and base plates, Ugh
Acrylic DTM is to be used again. Just foam rolling it on. 
Anyone need extra work? Lol


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## Eagle Cap Painter (Nov 14, 2016)

Chemical stripper?


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## ridesarize (Jun 19, 2012)

Eagle Cap Painter said:


> Chemical stripper?


Oooh la la. 

My paint store manager told me that green sandpaper is supposedly for acrylic , and it helps prevent the blocking, but they don't sell it anymore.

I might have some at home though I need some for the machine sanders.


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## CApainter (Jun 29, 2007)

ridesarize said:


> Oooh la la.
> 
> My paint store manager told me that green sandpaper is supposedly for acrylic , and it helps prevent the blocking, but they don't sell it anymore.
> 
> I might have some at home though I need some for the machine sanders.


Why are you having to sand it so thoroughly if it's an acrylic DTM? You could technically apply another coat without even sanding. Is the homeowner really displeased with the current condition of the finish, or is this more a matter of color change?


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## ridesarize (Jun 19, 2012)

CApainter said:


> Why are you having to sand it so thoroughly if it's an acrylic DTM? You could technically apply another coat without even sanding. Is the homeowner really displeased with the current condition of the finish, or is this more a matter of color change?


 it's just an issue of being able to put a good quality lasting couple of coats of paint on. the existing finish is possibly 17 years old and was maintained, but I pressure washed the whole area and so some of the rail has a tiny bit of mold or mildew(most iminor issue). there is a lot of crackling in places of the rail and sometimes the bottom of those cross members are cracked and you don't notice it until you look under them.

I figured for all the places where the paint was in good condition I would give it a light scuff at least.. but those areas have a lot of sheen still compared to where I sanded complete. So my goal is to sand the top coat and not get down to metal but that's inevitable in some spots. So now I decided to aerosol Prime probably the majority of the rail with cold galvanized metal primer

So I'm going to sand out a section for each day and prime it before I leave so those spots don't rust. I won't be able to get to it with the DTM fast enough so have to Prime. Plus primer makes everything better

1st pic most rusty spot at base
2nd pic average post base, crackly, failing
4th pic, worst failing spot only about 12-16 feet long.


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## CApainter (Jun 29, 2007)

Wow! you're not kidding. That topcoat looks like it was applied over a primer that wasn't ready.

Obviously, the best practice would suggest removing all of the paint. But unless you're getting paid for that amount of labor, you've got to draw the line somewhere. What are the homeowner's expectations?


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## ridesarize (Jun 19, 2012)

CApainter said:


> Wow! you're not kidding. That topcoat looks like it was applied over a primer that wasn't ready.
> 
> Obviously, the best practice would suggest removing all of the paint. But unless you're getting paid for that amount of labor, you've got to draw the line somewhere. What are the homeowner's expectations?


 I will be removing the bad paint.

They just want a good quality job. One that will last as long as possible since this is a big deal to do this rail. T &M. Said use the best product and treat it like it was my own railing to paint. It's gonna look awesome. The finish is Black with Blue in it. 

I opted for acrylic Impervex for ease of application (I hope) and from my BM store's suggestion.

There is a lot of existing paint in decent shape, i just showed the worst.


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## kmp (Jan 30, 2011)

Angle grinder with a wire cup on it. You will take it down to bare metal real quick but it will fit in more places than a random orbit.


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## lilpaintchic (Jul 9, 2014)

kmp said:


> Angle grinder with a wire cup on it. You will take it down to bare metal real quick but it will fit in more places than a random orbit.


Yup. Quit screwing around the hard way and get a wire wheel on an angle grinder. You can then sand some things out just to smooth em out but that'll be a much more efficient use of time and effort.
That or a chemical stripper on the bad parts....id just grab an angle grinder.


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## woodcoyote (Dec 30, 2012)

kmp said:


> Angle grinder with a wire cup on it. You will take it down to bare metal real quick but it will fit in more places than a random orbit.


You can use a flap disk as well, the cup wire works pretty decently too. 

Instead of using that purple 3m paper I'd swap out and use a rough drywall sanding sponge. They are cheaper, last longer, and won't burn up as fast as the paper. Some places don't like to sell them because they are pretty rough for drywall, so you can sometimes get special prices for them to unload them. 

Another option that might work would be to knock off the loose stuff and try and lock in the old stuff using something like Prime RX or XIM Peel Bond. A couple of coats and smooth things out, top coat. Maybe just try 1 rail to see how it might work. I'd rather spend 2 hours experimenting than 2 or 3 extra days or more doing it the hard way.

But it all comes down to expectations and what they are paying you for...so, who knows with T&M, you might get rich.


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## MikeCalifornia (Aug 26, 2012)

I would recommend the new acrylic urethane from SW if that is your company choice. I don't think the recoat time is all that quick, but its a nice product that will hold up better than standard DTM.


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## ridesarize (Jun 19, 2012)

So today I finish sanded and cleaned, and aerosol primed the first 20 some feet. 
Then machine and hand sanded another 20+ feet, cleaned and primed, using rustoleum cold galvanizing compound. 

I used the dts400 to quickly buzz the top rail, vertical posts and base plates. Then followed up with a quick hand sand scuff, and sanded the small tubes by hand. It wasn't too bad actually, was just dirty black, dusty, and reaching both sides of the posts is a chore. Horizontal tubes were reachable from one side of railing since I could wrap the paper around it easily.

I didn't use the LS130 at all today. Hand sanding the small tubes was probably quicker by hand and it didn't block up too bad that way. Just had to get into it and keep going. 
I did show up with several types of paper, and grits, and sponges and pads, just in case, but the purple did well. 
Sanding allowed me to take off or scuff the top layer of black, and left most of the original primer and first coat black so it became pretty smooth without grinding all then finishing with sanding. 

I thought about the grinder, and wire cup brush, which I have both. I can bring them tomorrow and try it. But grinding/wiring brushing on both sides of the rail high and low would be tough with a heavy grinder. How to get close to the glass or masking near base plates is a head scratcher too. My dts and/or hand sanding gets right in there. 

Thanks for all the input and if it doesn't rain tomorrow, I'll keep going.


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## woodcoyote (Dec 30, 2012)

What are you planning to top-coat with? Just curious.

Looks like the prep is turning out pretty good.


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## PACman (Oct 24, 2014)

Try wetting the sandpaper with some water.


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## lilpaintchic (Jul 9, 2014)

Grab a couple of cardboard shields to help keep the grinder off the glass and off the deck. You can double it up, cut to size, and otherwise manipulate them and tape them up as a bumper. If you're only using the grinder for the really bad parts it shouldn't be too bad I'd think. 
You've done and excellent job so far (as usual for you )
I do hope the rain holds off for just a little while longer! Yes, I know we need it, but once it starts, well, it's Seattle....it won't stop till about July.:/


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## ridesarize (Jun 19, 2012)

woodcoyote said:


> What are you planning to top-coat with? Just curious.
> 
> Looks like the prep is turning out pretty good.


BM Impervex. gloss or high gloss. 

I went to BM and looked into the ultra spec dtms and store manager said he'd go with the impervex. Don't recall using it before so I'm just trusting it's good. 

I'd like to do oil really but I was hoping acrylic makes it more feasable.

Thanks lilpaintchic woodcoyote and all


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## PACman (Oct 24, 2014)

I'd sandblast it myself.


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## ridesarize (Jun 19, 2012)

I'd hire a pro if it were my rail.... lol


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## Betheweb (Jul 26, 2016)

Stipping discs are obnoxiously expensive, but you don't have that much surface area. That's what I would try.


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## ridesarize (Jun 19, 2012)

Betheweb said:


> Stipping discs are obnoxiously expensive, but you don't have that much surface area. That's what I would try.
> 
> https://youtu.be/odQWP6RfF3o


Cool idea!


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## CApainter (Jun 29, 2007)

The problem with mechanically grinding narrow surfaces, like hand rails, is it often leaves an uneven surface unless you completely remove the paint to bare steel. And given the angles, you end up shooting dust and debris everywhere. I think you're going about it in the best way possible ridersize


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## Romanski (May 4, 2008)

CApainter said:


> The problem with mechanically grinding narrow surfaces, like hand rails, is it often leaves an uneven surface unless you completely remove the paint to bare steel. And given the angles, you end up shooting dust and debris everywhere. I think you're going about it in the best way possible ridersize


Not to mention, I doubt I'd walk up to the painter who used a 3 HP grinder, echoing that noise across my property for days to ask if he would come paint my house.


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## Toolseeker (May 25, 2017)

I assume POR 15 is out of the question. At the beginning I mean, I don't think I would use now though.


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## PNW Painter (Sep 5, 2013)

It might be unconventional, but you could wipe off the old coating with Denatured alcohol. 

Of course at this point you're probably almost finished.


Sent from my iPhone using Tapatalk


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## ridesarize (Jun 19, 2012)

PNW Painter said:


> It might be unconventional, but you could wipe off the old coating with Denatured alcohol.
> 
> Of course at this point you're probably almost finished.
> 
> ...


I'm getting there...I took Friday off because of the morning rain... so 3 day weekend.
Got back to it today. Used different stuff to see what would get me through. I hit the bases by hand with blue Norton 100 grit. Worked like a charm. Used the ls130 again on top rails, dts to buzz verticals. Also used the dts to buzz the top rail a few sections when I was going with it. Then still followed up with either worn 100 grit or new 180 everywhere but bases. Sanded till the crackled stuff was gone. The L S130 got through that worst handrail paint fail in little time, little effort, with a tiny patience.

I almost threw water on it to wet sand but not really. Sanding worked if I just kept at it. I just had to get over the fact it was a lot work. I didnt even show pics of the last 60 feet, so I have more to go.

I'll see what happens with the denatured al, but I suspect some melty paint. If it removes the top layer only it might be perfect. 

Thanks all


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## lilpaintchic (Jul 9, 2014)

I sure do admire your tenacity...i have a fair amount of patience, but the amount of patience required on that would probably kill me or At least send me to the looney bin if I had to do it all myself.


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## Stretch67 (Oct 7, 2013)

Obviously not going to work if your doing it solo. But we have a few commercial campuses that have us do all their wrought iron stuff. And there's a LOT of it! We have been vapor blasting it for several years now and it works very well. 

Something like you have there I think we could blast and prime on first day and finish coat second day. No it's not cheap, probably 8k for a 3 man crew for two days.

We use a lot of epoxies and urethanes for that type stuff. The first one we did is going on 10 years now, and still has that 'wet' look.


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## ridesarize (Jun 19, 2012)

Stretch67 said:


> Obviously not going to work if your doing it solo. But we have a few commercial campuses that have us do all their wrought iron stuff. And there's a LOT of it! We have been vapor blasting it for several years now and it works very well.
> 
> Something like you have there I think we could blast and prime on first day and finish coat second day. No it's not cheap, probably 8k for a 3 man crew for two days.
> 
> We use a lot of epoxies and urethanes for that type stuff. The first one we did is going on 10 years now, and still has that 'wet' look.


That would be awesome to do that procedure. Awesome idea.

Many challenges to this one, but I will succeed. . I wish my rolling perry scaffold (w/outriggers) would work on the outer side, but ground is uneven, grass is too thick and soft...and soft dirt underneath. I have 2 planks (&2 jacks) but I'd still have to move ladders and move a 20' plank around while painting. Too much on my plate already I think. 

I'll use the 16' ladder round the outside and have to hop over the rail the whole length lol.


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## lilpaintchic (Jul 9, 2014)

Well it's looking great! Hope you're making $ on it!


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## ridesarize (Jun 19, 2012)

lilpaintchic said:


> Well it's looking great! Hope you're making $ on it!


Thanks! It's not about money to me, especially on this one. I just want it to be a successful job really. These clients and friends are the nicest people ever.. repeat clients. So generous, easy going and very good to my boss and I. They deserve the best. I try to deliver that, no pressure lol.


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## ridesarize (Jun 19, 2012)

Railing system results::: mission successful!

I officially finished this project on Monday, which was house touch up related. Finished the dtm coating on Sat. I was rained out for 4 days straight last week in between coats . 
This one was a real challenge, but doable somehow. I put a lot of thought into how to go about the different steps and phases (some trial and error too). Was scratching my head about how I was going to access the inside and outside of the rail and be efficient. Turned out I had to do several things different or adapt a different technique across the whole thing,

I started painting the gate and post with a brush and foam mini roller. I quickly learned how you HAD to put it on nice and wet with a brush, yet with the mini roller you had to lay it out very thin and work extremely fast. Weird build up marks were created if you waited even 5-10 seconds to lay the spindles out because of the Impervex just dried instantly with that thin of a coat. So after the gate had dried I checked it out and the roller stipple, though nice and thin, it felt like crud and didn't give off a high gloss sheen. Not good. So I realized I had to brush everything. After doing so I found it was necessary, easier, and way better coverage/millage, better sheen.

Also ended up painting from the inside only. Reaching through rail, or leaning over, it was not easy and quite a pain on the back and body. Each piece including the posts have to be done both sides at a time top to bottom. Can't do half and make it look good, and with impervex you have little open time (especially in the high winds this place gets) Solution: Get the surface covered wet and lay it out at same time, and repeat a whole bunch of times.
It would have beem physically impossible for me to hop over to other side and move ladders down, and keep painting. 

So I did horizontals all seperate like 140 of them, then 33 posts and bases, then handrail, separate, about 135ft long in one continuous effort.


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## ridesarize (Jun 19, 2012)

A few pics


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## SemiproJohn (Jul 29, 2013)

Awesome looking work! And your description of how you went about this made me, well, tired! Painting all that from one side had to be exhausting.


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## ridesarize (Jun 19, 2012)

Cool scenery too. The Rich passage in between Bainbridge island on the right and Poulsbo on the left.

If you want to see a couple short clips of me using the dts400 on the rail, or me brushing the handrail with deer in playing in the background etc, I have those on Instagram. @xc_painter


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## ridesarize (Jun 19, 2012)

PNW Painter said:


> It might be unconventional, but you could wipe off the old coating with Denatured alcohol.
> 
> Of course at this point you're probably almost finished.
> 
> ...


I gave this a try. It melted the paint but at a slow rate (with lot of rubbing) so it wouldn't remove enough material on this rail project.


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## XYZ (Sep 27, 2017)

ridesarize said:


> A few pics


Looks very nice, smooth and shiny. Any close up pictures you could post? 
With this paint drying so fast I wonder how difficult it was to avoid 'brush lap marks" on the horizontal long pieces of the railing after moving few feet to the next section and brushing back into the "wet" painted section that by this time is already dry, are there any paint laps marks.

When I read your first post and saw the pictures I was cringing a bit thinking about logistics.
You did very nice job and used quality products.
Thanks for sharing your technique and journey.


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## ridesarize (Jun 19, 2012)

XYZ said:


> Looks very nice, smooth and shiny. Any close up pictures you could post?
> With this paint drying so fast I wonder how difficult it was to avoid 'brush lap marks" on the horizontal long pieces of the railing after moving few feet to the next section and brushing back into the "wet" painted section that by this time is already dry, are there any paint laps marks.
> 
> When I read your first post and saw the pictures I was cringing a bit thinking about logistics.
> ...


Thank you very much. 
I did the posts before the continual top rail. So those had dried.
The transition from the rail and dry posts blended great, cannot see a thing because I put it on wet. 
I painted the posts starting at top to bottom and made sure to paint wet, and quick., No letting it dry while on the same piece. 
The top rail took me 40 minutes nonstop brushing. Wet edge whole time. No lap marks show.


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## Sn0man (Sep 15, 2017)

ridesarize said:


> 1st pic most rusty spot at base
> 2nd pic average post base, crackly, failing
> 4th pic, worst failing spot only about 12-16 feet long.


Having looked at the photos I would hit that with an angle grinder and some 60 or 80 grit discs. It'll take the coating right off down to bare metal in no time. 

Of course the best method would be sandblasting but that wouldn't be economical.

EDIT: didn't see you had already finished this project - looks great!!


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## ridesarize (Jun 19, 2012)

Sn0man said:


> Having looked at the photos I would hit that with an angle grinder and some 60 or 80 grit discs. It'll take the coating right off down to bare metal in no time.
> 
> Of course the best method would be sandblasting but that wouldn't be economical.
> 
> EDIT: didn't see you had already finished this project - looks great!!


Thanks a lot, I think it turned out well too.


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