Marglass over epoxy primer?

T

TAguy16

Anyone have any problem with this? I've always put Marglass or Duraglass over epoxy primer when doing restorations and I have a factory seam where the body panels are overlapped then spotwelded together; this in lieu of using lead and in lieu of putting the Marglass right over coarsely sanded bare metal like the directions on the can say to do. I've never had a problem with doing this, at least that I know of, except for bubbling under the paint once. I read the bubbling can be caused by the heat of buffing over the fiberglass filler: I don't know if this is true or not but it sure ruined the paint job.

I avoid spreadable body filler like the plague, but sometimes using it can't be avoided. The alternative is using lead which has its own issues, but maybe they are less in the long run. The majority of failures I have had in my own work and seen in other's work has been in spreadable body fillers wreaking havoc down the road. With others' work I've had to redo in my shop it has been with people who have either used way too much Bondo (or something similar) in one place and/or putting it on over bare metal then the metal rusting underneath the filler. I don't do this so I've never had this happen, but I've had other problems with it (such as it shrinking over time) depite my best efforts to do everything I can to make it turn out successfully.

But I digress...
 
It is done often as far as putting items like Marglass, Duraglas type products over epoxy but we stopped recommending this a few years ago when a popular product stop sticking to the epoxy, within a few months the company fixed the problem and it started sticking again.
You will know if you have a problem as soon as you sand it if it does not peel off your good to go.
 
I use duraglass over epoxy all the time and no problems. That is with SPI . U-TECH 381 have had a few problems. I think the key is to let the epoxy dry very good hard to do in the production world. My test vehicle is a 2008 Town &Country I insalled quarter panel on my wifes driver and still looks great. I feel all products shrink and to have a successful repair must set in the sun to dry out, Would not believe how much work I lost as customer wants fast turn around just like on tv................
 
To anyone who would use something like USC Duraglass, I would recommend Evercoat Everglass instead. I've had better adhesion with it than with USC products, although I must admit I have not used Duraglass in a long time, it may have improved.
 
I believe 3M owns both the Marglass and Bondo names now. I don't know if that means anything in terms of the quality of the products changing, though. It's probably just more corporate consolidation: you know, the big fish eating the little fish so they can control the ocean more.
 
Anything good or bad to say about u-pol fantastic? Its all my local jobber has
 
i have been using vpa for a long time now . it is a very stable filler with little to no shrinkage. it is my go to filler when working on glass. does not ghost like duraglass type fillers .
 
ok i give....what is vpa?


LOL, don't feel bad! I been using Vette panel adhesive for around 30- 40 years and had no clue what VPA was and this was not the first time i saw the letters used.
 
Just got my gallon of Everglass. Instructions say grind all paint off before applying. Now I am searching the forums. I don't want to have to redo any paint work. I have 2 coats of SPI epoxy primer on the truck bed sides and fenders. What is the final word? Do I need to sand down to bare metal on the spots that need filler work?
 
Boy, have we gone round and round with this over the years! Evercoat won't recommend a substrate other than metal because they can't know what exactly it is or how you applied it. Obviously from their perspective, clean metal is the safest option because they don't have to deal with tech support from incorrect primer procedures. But it's not the best option. If you have a base of recently and properly applied SPI epoxy, there is virtually nothing better than that from a longevity and corrosion protection standpoint. If the epoxy is outside the seven day window and has not been exposed to the elements, just thoroughly scuff the epoxy, clean it, then apply the filler. Inside seven days, and you don't even need to sand.
 
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