Working With DURAFLEX?

Anything goes in the world of fiberglass and plastic



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PostPosted: Wed Oct 26, 2016 8:51 am
I just wanted to know if what all these Duraflex fiberglass companies say is true.

Do these fiberglass products really come adequately primmed as advertised? Just slap on a couple coats of paint and clear?
Good to go?

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PostPosted: Wed Oct 26, 2016 10:50 am
The parts are coming to you in a "sandable gel coat" which is kind of a good/bad thing.... The good...yes, it is a sandable primer which you could, theoretically, just sand and go. The bad...parts can be "flashed" together in sub-assembled piece creating air pockets/voids which you simply cannot see....the bottom line is those voids can contain gasses which can come out later as a surface warms up in the sun. Another thing I've seen is contamination in that sandable primer which is coming directly from contact with the "mold butter" or parting agent that is used. You'll see fisheyes form and other nasties.
You're only protection on these parts is vigilance on YOUR part. If you can, try and talk to someone that has bought from the vendor before or has the parts on a car. Local car clubs are your best be there for your particular make. Next, check out if the parts are being made here, Canada, Mexico, Brazil, etc. We are currently seeing higher quality fiberglass coming from those countries. IF the parts are being made in China, Malaysia, India, or Viet Nam its' going to be a roll of the dice on quality. Not saying you couldn't get a decent part but they can be pretty terrible. Just saw on Gas Monkey the other night an $11000 styling kit they bought for a Porsche. Only a nose and two front fenders....NOTHING fit, not even close, and the surfaces looked pretty poor to me.
As far as the kit cars I build... If I even smell "resin" when I get them I put everything out in the sun for two weeks, no exceptions. They need to get all that shrinking over with.... I then use a solvent degreaser and a water based degreaser. Let it dry thoroughly. Check the inside of the parts (sometimes easily visible on the outside as well) for your mold seam areas and mark out on the outside. I sand those seams back on the outside until I see the clear resinous surface. Now you should be seeing both bubbles in the surface and air voids. I open those up with a Dremel tool and will fill with the compatible resin the body parts were built with or an epoxy resin sand and level.
Other than these seams you can leave the rest of the sandable primer if you want or simply sand it down, lay down an epoxy seal coat, then build with regular high build primers from there.
Bottom line, would I just sand and go with what's there? You could, but I wouldn't.
Metal, wood, fiberglass, we work it all... www.furniturephysicians.com We can restore the irreplaceable!



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PostPosted: Thu Oct 27, 2016 7:44 am
DarrelK wrote:The parts are coming to you in a "sandable gel coat" which is kind of a good/bad thing.... The good...yes, it is a sandable primer which you could, theoretically, just sand and go. The bad...parts can be "flashed" together in sub-assembled piece creating air pockets/voids which you simply cannot see....the bottom line is those voids can contain gasses which can come out later as a surface warms up in the sun. Another thing I've seen is contamination in that sandable primer which is coming directly from contact with the "mold butter" or parting agent that is used. You'll see fisheyes form and other nasties.
You're only protection on these parts is vigilance on YOUR part. If you can, try and talk to someone that has bought from the vendor before or has the parts on a car. Local car clubs are your best be there for your particular make. Next, check out if the parts are being made here, Canada, Mexico, Brazil, etc. We are currently seeing higher quality fiberglass coming from those countries. IF the parts are being made in China, Malaysia, India, or Viet Nam its' going to be a roll of the dice on quality. Not saying you couldn't get a decent part but they can be pretty terrible. Just saw on Gas Monkey the other night an $11000 styling kit they bought for a Porsche. Only a nose and two front fenders....NOTHING fit, not even close, and the surfaces looked pretty poor to me.
As far as the kit cars I build... If I even smell "resin" when I get them I put everything out in the sun for two weeks, no exceptions. They need to get all that shrinking over with.... I then use a solvent degreaser and a water based degreaser. Let it dry thoroughly. Check the inside of the parts (sometimes easily visible on the outside as well) for your mold seam areas and mark out on the outside. I sand those seams back on the outside until I see the clear resinous surface. Now you should be seeing both bubbles in the surface and air voids. I open those up with a Dremel tool and will fill with the compatible resin the body parts were built with or an epoxy resin sand and level.
Other than these seams you can leave the rest of the sandable primer if you want or simply sand it down, lay down an epoxy seal coat, then build with regular high build primers from there.
Bottom line, would I just sand and go with what's there? You could, but I wouldn't.


I have seen this product before in person, finished and installed. I now understand what the bubbleing was which I originally believed to be a bad job.

I am sorry but I did not really understand what you had proposed. If I understand you correctly, you are proposing I leave the hood out in the sun for about a week or two. This should expose any of the pockets of trapt gases or air. Then I dremel through them and refinish them with a compatible epoxy/filler?

P.S.
I am no fan of Duraflex. I firmly believe you get what you pay for. Unfortunately I am limited with my options on this car.

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PostPosted: Thu Oct 27, 2016 10:24 am
Yeah, you're close there on understanding this..... Setting the piece out in the sun let's the entire piece do it's final shrinking. This will not expose the air voids but will make the piece much more stable for the rest of your work. You'll have to sand back that sandable primer gel coat to "see" the air pockets that need Dremeled.
Yeah, Duraflex....everybody "thinks" that product was put out there to improve the quality of parts when, this is just my opinion (but shared by many other fiberglass craftspeople), I think it is sold to the manufacturer as being easier to "pop" the pieces from molds with little to no damage and less prep. before shipping. I don't like the stuff, period.
Metal, wood, fiberglass, we work it all... www.furniturephysicians.com We can restore the irreplaceable!

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