OmakZ Posted February 24, 2012 Share Posted February 24, 2012 I cut the cracks out of my dash, filled them with expanding foam, glassed over portions of the top, smoothed it all with bondo, and topcoated it with SEM interior paint. It looks great and is pretty durable (if you remind me I might be able to find pix). The only problem was that I had the dash out of the car for so long that it relaxed it's shape a little. When I put it back in, it was too wide for the car and squeezing it to match the mounting holes made the new top surface warp a little bit around the cracks. Where it was totally smooth when I finished working on it, there are now a few small waves/ridges. I would recommend doing this work with the dash in a jig or in the car with the windshield removed so it fits correctly. Looking good so far though. Quote Link to comment Share on other sites More sharing options...
Jasonmreiss Posted February 24, 2012 Author Share Posted February 24, 2012 A little progress, and I'm pretty sure I have brain damage from the fumes Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted February 25, 2012 Share Posted February 25, 2012 I cut the cracks out of my dash, filled them with expanding foam, glassed over portions of the top, smoothed it all with bondo, and topcoated it with SEM interior paint. It looks great and is pretty durable (if you remind me I might be able to find pix). The only problem was that I had the dash out of the car for so long that it relaxed it's shape a little. When I put it back in, it was too wide for the car and squeezing it to match the mounting holes made the new top surface warp a little bit around the cracks. Where it was totally smooth when I finished working on it, there are now a few small waves/ridges. I would recommend doing this work with the dash in a jig or in the car with the windshield removed so it fits correctly. Looking good so far though. Did you use csm or cloth? Quote Link to comment Share on other sites More sharing options...
OmakZ Posted February 25, 2012 Share Posted February 25, 2012 Did you use csm or cloth? Cloth, and I probably could have laid it down thicker but I didn't want a plastic dash. As it turns out, it wouldn't have fit if I'd made it more rigid. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted February 25, 2012 Share Posted February 25, 2012 Cloth, and I probably could have laid it down thicker but I didn't want a plastic dash. As it turns out, it wouldn't have fit if I'd made it more rigid. I'm just wondering if the reason it didn't fit is because it sagged just sitting there like you say, or if it's because the cloth warped it. Quote Link to comment Share on other sites More sharing options...
Jasonmreiss Posted February 25, 2012 Author Share Posted February 25, 2012 I remember when this was my thread, screw you guys I'm going home! Lol just kidding . I started the bondo tonight, I'll finish it tomorrow, then pics. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted February 26, 2012 Share Posted February 26, 2012 In retrospect I bet that much of the recracking problems are really because great stuff is so unstable. I found that out the hard way when I was using it to make a bunch of molds because it's so easy to use. Come back a week later and a parting line is now a 1/4" gap. Even though it's supposedly cured in 24 hours, I'd wait a month before I did anything to it because it keeps expanding slightly. That and I think it doesn't work well with temperature extremes. Often times I'd leave it overnight and the next day the paint would be cracked all over the place. I suppose the original foam could expand and contract similarly, which is why using hard bondo to fill gaps doesn't work out so well. You'll be glad you spend the extra time covering it with glass. There, I brought the conversation full circle Quote Link to comment Share on other sites More sharing options...
Jasonmreiss Posted February 26, 2012 Author Share Posted February 26, 2012 Well I think I failed miserably :-/ I tried to get it as smooth as possible, and it seemed ok, then I sprayed on some adhesive promoter, then 5 coats of high build primer. Once the primer was on, all the imperfections became painfully visible. Not sure what to do now, more sanding maybe? More bondo? I've never used it before so don't know how thick I can go, or if I have the skills to shape it properly. I also dont want a 200 pound dash... Quote Link to comment Share on other sites More sharing options...
Jasonmreiss Posted February 26, 2012 Author Share Posted February 26, 2012 Oh, and I didn't fill the cracks with bondo, I just fiberglassed over them Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted February 27, 2012 Share Posted February 27, 2012 Oh no! I could have told you not to bondo the whole thing, I thought you were just going to do the glass? I've been there, you think the bondo will go on smooth and if all else fails all you have to do is sand it to perfection, nope. The problem with bondo is it's not the easiest thing to sand and even harder to feather (especially if it borders something softer because as you sand where the edges around the bondo become valleys) because it just humps in the middle (the edges sand away faster). Bondo never goes on perfectly smooth or to the shape you want with a sweep, the key is you have to intentionally apply too much and sand it to down shape. Besides, if you swept it in perfectly, it would still be low once it cured because it shrinks a little. If you absolutely had to bondo the whole thing, the only way to get it nice in the end is to do just that, the ENTIRE thing. A thick coat with none of the underlying material exposed. Then you sand it to shape without going all the way through it, but again this will take forever because it's to complex to power sand, and you'll go through quite a bit of sandpaper as it clogs. You can wet sand it to make it a little easier, but it does absorb moisture a bit so you have to make sure it dries out for quite a while before you paint it. In the state it's in now, you have a lot of pits to fill before you finish it, and there's still the football texture where the plastic is uncovered. Fill the major low spots, fine grit power sand what you can get to (don't over do it), finish the corners and contours by hand--don't try to get it perfect or you'll sand too far! Paint several more coats and resand. It will still need some touching up but sanding the paint is easier than sanding the bondo, so keep painting and sanding until the little uneven areas are blended out. Normally you glass over the top of the bondo, not the other way around, because the condition of the bondo matters very little--you'd have to sand the glass either way. In fact I'd remove most of what you have there because like you said it's just adding a bunch of weight and making the dash gratuitously thicker.. A thick layer of glass is a better starting point though than a bunch of uneven bondo because the resin should have flowed out some to make it somewhat uniform. Once the glass is fairly smooth you do the same painting and sanding as you would over bondo, but hopefully it won't take as much paint because the glass shouldn't have as many pits etc. and won't absorb the paint (The glass shouldn't be uneven enough to warrant the use of bondo at all.) If there are some really low spots, I'd sooner just add another little patch of glass because it's easier to feather the same material into itself rather than something hard over something soft. By the time you paint and sand enough coats to get rid of the football pattern, the glass portion should be in pretty good shape. If the sandpaper clogs too easily from the glass or the bondo, just wait a week and it will go 100 times quicker. Even a hot patch that should be cured in ten minutes, I usually leave alone for several days just because I don't want to battle with that nonsense. Even though pure resin is harder than bondo it still feels easier to sand because the paper doesn't clog as much, (although it dulls a little quicker). If it makes you feel any better, I've been getting my ass kicked by a big mold for months now because I just keep finding a million more ways that don't work. Don't give up! If you have any other ideas just ask because I might be able to warn you first if they don't work, believe me I'm FULL of ideas that didn't work. Quote Link to comment Share on other sites More sharing options...
OmakZ Posted February 27, 2012 Share Posted February 27, 2012 FWIW, I put the bondo down over my glass and it worked. Granted I used a very small amount but the resin is a hard surface so feathering it isn't that bad. It just takes a lot of time and patience (probably 10+ hours of: fill, primer, cross-sand way down, repeat). They best tip I can give other than patience is to topcoat the whole thing in some kind of texture so you don't notice the small imperfections as easily. Quote Link to comment Share on other sites More sharing options...
Jasonmreiss Posted February 27, 2012 Author Share Posted February 27, 2012 Yeah I gave up on the smooth finish I think lol, good news is I put another thin coat of bondo on and it fixed the small part I tried it on. I also took a lot more time sanding. I'll finish the rest on Tuesday and put pics up. I sure don't mind screwing up though because I am learning a lot. I've been a gear head for 25 years and never used bondo before. I totally suck at it but am getting better. Besides, I can always just sand down to where I started originally and start over. Fwiw thanks for all the advice, I love this forum Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted February 28, 2012 Share Posted February 28, 2012 That's the great thing about composites, it's never too late to go back. Quote Link to comment Share on other sites More sharing options...
Jasonmreiss Posted April 15, 2012 Author Share Posted April 15, 2012 All done, it took a lot of attempts and still isn't perfect but good enough for now. Besides if one of the people talking about cf dashes actually starts making them then I can always replace it later Quote Link to comment Share on other sites More sharing options...
southern280z Posted July 15, 2013 Share Posted July 15, 2013 I want to fiberglass my dash. Should I make a mold of the original dash or just glass right over it? If anyone has done this or knows which is a better way of doing it, please let me know. Quote Link to comment Share on other sites More sharing options...
SUNNY Z Posted July 15, 2013 Share Posted July 15, 2013 I want to fiberglass my dash. Should I make a mold of the original dash or just glass right over it? If anyone has done this or knows which is a better way of doing it, please let me know. Did you read any of the thread? Both have been done. Fiberglassing over your current dash will be less time consuming, I can nearly guarantee it. Quote Link to comment Share on other sites More sharing options...
southern280z Posted July 15, 2013 Share Posted July 15, 2013 Thanks, Im new to the whole fabricating thing, I appreciate the insight and thats what I will do! Quote Link to comment Share on other sites More sharing options...
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