DTSFab.com (Desert, Trail and Sand)
The Machine Shop => Fiberglass/Composite Fabbin' => Topic started by: fabr on July 10, 2009, 07:49:10 PM
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Thought I'd post these here.I'll move some of the beginning ones also. Still in rough stage .
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Maybe now? LOL!
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Now? ::)
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??? ??? ??? ::) ::) ;D ;D
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The following is one method of doing a plug for use in making a mold to pull finished parts from.There are other ways such as moldless construction if you will not need replacement parts later. This method is for a permanent mold to be made.
Step one. POLYESTER felt stretched over frame ,retained with elastic strap to keep tight. Then coat with polyester FG resin to stiffen.
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Next a load of standard MINIMAL POLYURETHANE spray foam and trim to rough shape a bit undersize to allow for a few layers of body filler to make a firm plug .Discard the tube that comes with the foam,slightly heat the screw on nozzle and flatten into a flat fan nozzle.Spray away without shaking the foam up but a small bit before spraying.That makes a denser and easier to work foam.
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Shaping parts this size can be challenging.I even used a machette to make the large cuts and then you just start sanding with 40-80 grit paper on a body file.I do not use pnuematic tools .I find it easier to take a bit more time and that allows me more control at getting the shape right.
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So we end up here for now. These pics are of the plug with 1/2 gallon of POLYESTER high build primer surfacer. Ready for the first sanding and then however many final coats of high build primer surfacer and more sanding till final shape and finish part quality is achievede. This is important-the plug needs to be as good or better finish than you want the final part to be. Be SURE to use POLYESTER CATALYZED primer surfacer or you will meet disaster when you lay on the FG for the mold. More to come.
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So what we have seen so far is just a mold for the figerglass panels that you'll use?? How thick are these, cause I would think once you put the fiberglass panels one those molds then they will be that much larger than car. Would this cause a fit problem?? I'm sure you have it worked into the design of, just wondering.
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No,this is the plug. A plug has the exact shape and size of the final body panel. It matches the hoods outside dimensions perfectly. It is an exact rendition of the final body panel but is not the panel-just a plug or pattern if you will. It is of the same thickness as the final part in all areas such as where it wraps the chassis tubes for a snup "snap on"fit on the upper edge and also matches the tube countours at the bottom edge of the frame for a nice look that also stiffens/straightens the bottom edge. This "wrap around /snap on " fit minimizes greatly the need for dzuses that will attach the panels for easy on and off use. THe foam is used to develop the countours that the body panel will have such as the indented area down the side.
After this piece is done ,waxed 3-4 layers with high temp mold wax and a mold release also applied I will lay on 4-5 layers of 1.5 oz. FG cloth and resin and many stiffening ribs to make the actual mold.That step comes soon as I get this plug to perfect final shape/finish. The better the plug -the better the final part.
After the mold is made the actual body panel will be laid up from 3 layers of 1.5oz. FG mat and resin. Total panel thickness of the actual part that will be pulled from the mold anywhere is approx .090 . Strong ,lightweight,easily replacable if damaged since I have the mold from this process. The plug is many times destroyed when removing from the mold.
I THINK artie is going to show a "moldless" method that works well for one off pieces. This way has more steps but allows me to duplicate any piece quickly and easily if the need arises. The dash I made in the Fabrs dash thread was an example of that method. I doubt that I'll ever damage the dash so I chose the quicker ,easier way for it. Body panels tho------I MIGHT damage them sometime. AW,surely not,I mean I drive like a little old lady.
Ask any questions you wish if I've made this too confusing. ;D I'll be glad to answer. Bugpac was doing some cacumn bagging FG work but has stopped doing it. Vacumn bagging is a very good way to do a part like my side panels and hood but they are large enough that they take too much time to lay up,bag,pull a vacumn on before the resin sets up.Gel time for a properly polyester resin is approx 20 minutes. On a part the size of these it takes more than that just to put on one layer. The resin to be used to allow the working time needed is EPOXY resin that is MUCH MUCH more expensive.It is stronger and allows ecen lighter panels but is cost prohibitive for this. BTW,none of this is cheap to do. SHop around for your best deals. There can be very wide price differences.
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Looks Effen GOOD Master ;) well done! ee:
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Well,thank you. I'm hoping I'm not making this too vague. I've had a lot of trouble over time learning some good techniques and what materials to use. Seems like the people that know how to do this stuff guard its' "secrets" like they were gold. Sort of like many pro welders do. Several years ago I found a man in Broken Arrow,Oklahoma that was the most knowlegable,willing to share expertise man I have ever met about FG techniques. I cannot thank him enough and I always buy my bulk FG supplies from no matter what he charges me for it. He has though always been very competetive on his pricing and also his resins are ALWAYS fresh. That's very important to a successful FG project.Many times if you just run down to the auto store and buy a gallon or quart of resin and a small piece og cloth/mat the resin has thickened with age and will not saturate the mat easily and it will make too thick a piece since it will not flow well. For many things that is not much of an issue but for large parts it becomes VERY important. I cannot stress that enough. The other thing that cannot be emphazied strongly enough is PROPER CATALYZATION of the resin. Any reputable dealer in resins will have a temperature chart that tells you the EXACT ratio to use based on temperature of the RESIN. Proper catalyst use will allow a reliable working time and consistent shrinkage so the part will have minimal distortion when pulled from the mold.
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Ok got it now. You made a plug (inside piece that we all see) to make the mold (outside piece) from that you will make the finished piece (inside) from.
Great post!!
Thinking I might try this, 1 step mode for a dash.
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Yep,you got it now. I'll be doing,well beginning , the actual mold hopefull tomorrow.Still have a bit of finish work to do to the plug.Another 3-4 hours shape sanding and removing all small blemishes and should be good to go for the mold making.
The moldless method is great for true one off pieces that are not likely to ever need duplicating. I suggest it as a great way to start FG work.DO you understand the proper techniques for it? Are you aware of the need for stuff like PVA and what mats/cloths are available and what weights will help you get the results you want? Any questions just ask and I'll put about 2 cents worth of opinion out . ;D
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Yep,you got it now. I'll be doing,well beginning , the actual mold hopefull tomorrow.Still have a bit of finish work to do to the plug.Another 3-4 hours shape sanding and removing all small blemishes and should be good to go for the mold making.
The moldless method is great for true one off pieces that are not likely to ever need duplicating. I suggest it as a great way to start FG work.DO you understand the proper techniques for it? Are you aware of the need for stuff like PVA and what mats/cloths are available and what weights will help you get the results you want? Any questions just ask and I'll put about 2 cents worth of opinion out . ;D
Yes. ;D I've looked at the dash thread and it would be nice if it was condensed like this with showing step 1, step 2, etc.
Thanks!
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You just want me to do some work! LOL!!! Yeah ,you're right tho.
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Sad,sad day. After many intimate hours together we end our time together in shambles.
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However with every ending is a new beginning. My life with an actual right side body panel begins. Time now to make a panel. Unfortunately many times a plug is destroyed dur to it's rigid nature from its thickness. That makes it necessary to break it out of the mold ,destroying it of course. Better get it right the first time,huh? ;) . The actual part will easily remove though since it is pliable.
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Is that the part or the mold?
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Mold.I'll make the panel Sunday or Monday. I'm meeting up for a bit with fastcorvairs Saturday night at LS so won't get to it till then. I spent this evening final finishing the mold after breaking the plug out of it last night and grinding perimeter to size. I'm real happy with the result. Should make a real nice part with minimal if any prepaint prep but for wet sanding.
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Got right side plug 95% ready to make mold. Should have panel by weekend. This plug/mold/part will take about 1/4 the time of the first.
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Git Er Done!
Ohhh yeahhhh ;)
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Added a nose trunk.
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Dirty,dirty body.Body panels finally done ready for mounting/final fit. ;D
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How are you going to hold the hood open? Or is that where Mrs. Faber come in?
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What? You didn't see the prop? LOL!! No, it will have a gas cylinder on it. Of course for now my hard head is doing the job.
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I have done it that way for years. Hence on hair on my head.
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I'm trying to preserve what I have left! LOL!!!