# oversanding durabond



## HQP2005 (Feb 14, 2012)

After a few coats of durabond, i covered everything with pre-mix, but had to much build up on the edges of the patch, which i had to aggressivly sand down to level out hump.

sanding the durabond created a glossy surface (almost like glass)

Problem;

2 days after priming patches, ran a piece of blue tape under window to paint bottom trim piece, and when removing tape, primer came off with it, but just at the edges where I had sanded the humps out. began to randomly test areas with tape, and primer bonded everywhere except where i had sanded the humps down. I have now scaped the primer from these areas have come up with 3 ways to proceed, and am curious which you think is the better solution.

1. Re-prime areas with a bonding primer (STIX), Skim to level out scraped primer, then reprime.

or 

2. cover areas with plaster weld, skim and prime

3. Add plaster-weld to mud, skim and prime.

Any other suggestion would be greatly appreciated.

thanks


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## modernfinish (Mar 20, 2013)

Sounds like primer was dry to touch but not cured. Use a different primer is what I'd do.


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## Delta Painting (Apr 27, 2010)

Or the durabond had some moisture in it still. I have had that happen when trying to sand it out when not dryed out all the way it almost causes a burnishing on the surface of the mud.


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## TJ Paint (Jun 18, 2009)

The culprit: surface had no tooth, and your primer was no match

The solution: either create a tooth by mechanical means or recoat with mud that will remain more porous, or use a bonding primer. 

Cheers.


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## TERRY365PAINTER (Jul 26, 2009)

Why use a primer at all ? . 
I use flat wall paints for most of my repair work . 
unless there is water damage or stain problem . 
plus wb primers take time to cure . 
Guards for everything else.


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## plainpainter (Nov 6, 2007)

durabond is similar to plaster in that they can both be 'hot'. People are always talking about mechanical bond or 'tooth' - but remember, in the northeast where we trowell plaster to a smooth glass like surface, primers stick fine as long as you obey the procedures. If you are going to paint/prime directly to durabond, then you are going to have to wait a similar amount of time like in plaster, anywhere from 2 weeks to months. Or topcoat with pre-mixed mud and cover it so the paint doesn't touch the durabond.

Edit: I'd go with #2 of your choices, since you sanded/burnished the durabond - it would probably be hard for premixed mud to stick as well - since the resins are no different than in paint. Give the durabond a little vinegar/water wipe down to help keep the 'hotness' to a minimum, i.e. high ph.


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## TJ Paint (Jun 18, 2009)

plainpainter said:


> then you are going to have to wait a similar amount of time like in plaster, anywhere from 2 weeks to months. Or topcoat with pre-mixed mud and cover it so the paint doesn't touch the durabond.


Waiting two weeks to a month is ridiculously impractical for wall repair. Sure, primer will bond to smooth plaster/durabond but not in 24 hrs after applying it. There's a cure time. Since the context of this discussion is wall repair on a repaint project, we should consider a practical means to solve the problem brought up.
Durabond, in my opinion is for first coat heavy fill and not good for a final finish. Use the light weight or normal mud for the finish coats. You probably wouldn't have any issues doing it this way. Durabond sands horribly in the first place.


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## kdpaint (Aug 14, 2010)

Speaking hypothetically of course, :whistling2: if I had that issue, where a patch was sanded so Durabond was "peeking out" around the edges, I would BIN it if I was concerned about adhesion of subsequent coatings. 

I'm not proud, but back in my apartment turnover painting days, we would sometimes (big rush) patch damaged plaster and rock with 1 coat of Durabond, scrape ridges before it set, smooth it with a wet knife, dry it with a fan, and hit it with BIN. We would let it sit for the morning, and top coat it maybe 5-7 hours later. Coming back to those apartment later, there were 0 problems with adhesion.


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## more_prep (Dec 7, 2009)

I just used Durabond 90 as a finish fill coat around several door casings....I wanted a hard surface for two reasons. First, to match the existing plaster kinda, and second, so I could power sand it with a festool rt400. The power sanding worked nicely with 120 paper, giving me a flat surface that blended seamlessly with the plaster. Knowing primer doesn't stick well to either durabond or compound, for that matter, I brushed on Guardz. This worked well, except that it caused the durabond patches to swell in a couple of areas, and they remained slightly swollen. The Guardz + durabond worked well overall, I would say. Faster turnaround time than waiting for multiple coats of durabond, compound, primer. Nice solid, smooth surface.


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## BrushJockey (Mar 15, 2009)

Gardz can bond to it and also is good to use over plaster- will not be affected by the Ph.


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## kdpaint (Aug 14, 2010)

Was the durabond a thick-ish coat? Only wondering because if it was more than, say, 1/3" or so, it may not have been 100% dry and the Gardz re-wet the mud making it swell a bit....just guessing. I love Gardz....


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## more_prep (Dec 7, 2009)

kdpaint said:


> Was the durabond a thick-ish coat? Only wondering because if it was more than, say, 1/3" or so, it may not have been 100% dry and the Gardz re-wet the mud making it swell a bit....just guessing. I love Gardz....


It was 1/16" to 1/8", and the areas that swelled were about 1/16"...no idea why some swelled while others didn't. One reason I used the Guardz was to prevent swelling with humidity changes -- I've often seen patches 
change with the weather after the finish coats are applied. I'm pretty
sure these were completely dry after sitting overnight, though.
Probably BIN doesn't swell the patches, since the alcohol would absorb,
rather than add to, any water in the patch. On the other hand, the BIN
doesn't penetrate as well.


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## Workaholic (Apr 17, 2007)

Edges became polished. Essentially like TJ said nothing to grab.


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## GrantsPainting (Feb 4, 2013)

All great comments. Also try using BIN. zinzer makes it in a can if you want.

Sometimes it easier to spread out more mud on the edges rather than sand down to another surface.


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