Weight loss.

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furrystump

furrystump

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So I knew the rear seat back in the car was pretty heavy. It being a fastback and folding down. With the intention of stuff being transported on top of it while folded down. I pulled it out and threw it on the scale. The seat back weighed 48 lbs. My goal, is to make a much lighter part that would be indistinguishable from the original. Be covered in the original seat cover and mount all the stock trim. I’m ok with it being fixed , unable to fold down. My goal was a 40 lbs reduction in weight. I plan of wet laying carbon fiber over rigid insulation, then break out the foam and glue small wooden blocks inside to accept the trim screws. Glue the original carpet on the back and install the fish emblem. Was happy the original carpet came off in one piece. I used a dado cutter on the table saw to rough out the shape.

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The finished form, which fits a bit loose because the carbon fiber will have some thickness.
 
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Made a small square to bridge the emblem area and laid the back up.
 
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First time playing with carbon fiber. Not perfectly smooth, but it is wet lay and its going to be covered by seat cover and carpet. Put it out in the sun and very quickly got to 153 degs! Chiseled out the foam last night after cutting access holes. Plan on using zip ties to hold the seat cover in place and fab up an aluminum mounting bracket. Its cooking in the trailer, might as well use the heat wave for something! The shell weighs 3.3 lbs. confident the total weight will be less than 10 lbs.

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The waves are from the mold release film printing through. The online video said it would be “forgiving” a bit a wrinkles. I’m sure that is true to an extent. They were laying up 6 layers to my 2. I just need it to hold the cover in the correct shape. I would get it smoother and more spray adhesive to make it stick to the foam better. if I was to do it again. Will probably do the cargo area floor and the trunk partition after this. The cargo floor is pretty heavy. Stamped steel, significant gauge.
 
@furrystump I am a retired materials and process engineer/chemist from Boeing. I have often thought of making some carbon fiber/epoxy articles in my garage. What resin system are you using?
 
Amazing! I have thought of doing stuff like this around my Dart but just the thought of the price scares me. How much $$ do you have invested in this so far?
 
IIRC some Petro chemicals desolve styrofoam. (I'm not mentioning gasoline as I'm sure there are safer alternatives)

Can you say napalm!
 
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US composites, was cheaper than West System for resin and other things. I have about $300ish invested. Ordered mold release wax and a gallon of PVA, a gallon of resin with hardener, pumps for them, and 5 yards of 50” wide 2x2 5.5 ounce fabric that was on clearance. The total was $265? $50 for a 4’x8’ pink rigid insulation foam. Have 5 feet left and 3/4 of the resin. Wasn’t fun chiseling it out, but would hate to have to deal with the melted leftovers if I dissolved it. Going to make front bumper brackets using molds and vacuum bagging. Just want them to hold the bumper on safely. Figure the steel ones are 3/8”? Buy a roll of 2” “tape” should be able to get about 20 layers per bracket. Probably stronger than the steel! The carbon fiber was probably on clearance because there is a very subtle wave in it as the light catches it that if you were going for the shiny carbon look, might make you unhappy.
 
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furrystump said:
US composites, was cheaper than West System for resin and other things. I have about $300ish invested. Ordered mold release wax and a gallon of PVA, a gallon of resin with hardener, pumps for them, and 5 yards of 50” wide 2x2 5.5 ounce fabric that was on clearance. The total was $265? $50 for a 4’x8’ pink rigid insulation foam. Have 5 feet left and 3/4 of the resin. Wasn’t fun chiseling it out, but would hate to have to deal with the melted leftovers if I dissolved it. Going to make front bumper brackets using molds and vacuum bagging. Just want them to hold the bumper on safely. Figure the steel ones are 3/8”? Buy a roll of 2” “tape” should be able to get about 20 layers per bracket. Probably stronger than the steel! The carbon fiber was probably on clearance because there is a very subtle wave in it as the light catches it that if you were going for the shiny carbon look, might make you unhappy.
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I went to school for plastics and auto body for 2 years, I've forgotten everything there is to know about doing fiberglass work, could I ask you some questions in the future, I've been wanting to build fenders and a hood for my 70 dart. Maybe the dash but not for a while.
Thanks.
 
Absolutely, but it’s my first time playing with it, so definitely NOT an expert. I found Easy Composites has a bunch of good video’s (wicked smart like engineers, but have videos with hobbiest in mind) and AJ Hartman Aero (production guy, not buying every super duper piece of equipment out there) What I learned is if you are looking to make engineered structural components like suspension parts. You should use the specialized equipment that really makes this stuff $$$$$$ to get into, but you can get good results without breaking the bank. For example ovens, required if you use PrePreg material other than that, you can just let it cure at ambient temp, but if using a vacuum you need a vacuum that can run for as long as it takes to cure. Vacuum bagging? The consumables can get expensive, but vacuum garment storage bags are cheap! (and no need to have vacuum running) Vacuum pumps are expensive, household vacuum creates about the 20% vacuum you’re looking for. You still need the peel ply and mat that allows air through and sucks up excess resin, but for just the hobbiest. You can vacuum bag a part for $30 in consumables not including the part. I plan on using garment bag, might double bag it just in case one bag leaks. An A body fender would be great! I can’t run them, but because of the shape of the originals, the mold would be a multi 3-4 piece mold and you would probably want to do the infusion process and cook it. The infusion process needs a vacuum pump running until it cures? So you probably need a real pump. A cheap pump or house vacuum running for HOURS probably won’t work. The AJ Aero guy looks like he just made a closet with racks in his shop with insulating foam with some style of small heater inside. Making a mold adds cost which for one off things seems wasteful? I’m going to make molds for my bumper brackets. They are not THAT complex, but strength matters with them. They have to safely hold on a steel bumper for me (rules). So I want to vacuum bag them. Total weight for the seat back is 9.5 lbs. Tonight I have to glue the carpet to the back and screw the trim around the edges. Glued small wooded blocks inside for the screws to bite into last night and made aluminum mounts to replace the hinges.
 
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furrystump said:
Absolutely, but it’s my first time playing with it, so definitely NOT an expert. I found Easy Composites has a bunch of good video’s (wicked smart like engineers, but have videos with hobbiest in mind) and AJ Hartman Aero (production guy, not buying every super duper piece of equipment out there) What I learned is if you are looking to make engineered structural components like suspension parts. You should use the specialized equipment that really makes this stuff $$$$$$ to get into, but you can get good results without breaking the bank. For example ovens, required if you use PrePreg material other than that, you can just let it cure at ambient temp, but if using a vacuum you need a vacuum that can run for as long as it takes to cure. Vacuum bagging? The consumables can get expensive, but vacuum garment storage bags are cheap! (and no need to have vacuum running) Vacuum pumps are expensive, household vacuum creates about the 20% vacuum you’re looking for. You still need the peel ply and mat that allows air through and sucks up excess resin, but for just the hobbiest. You can vacuum bag a part for $30 in consumables not including the part. I plan on using garment bag, might double bag it just in case one bag leaks. An A body fender would be great! I can’t run them, but because of the shape of the originals, the mold would be a multi 3-4 piece mold and you would probably want to do the infusion process and cook it. The infusion process needs a vacuum pump running until it cures? So you probably need a real pump. A cheap pump or house vacuum running for HOURS probably won’t work. The AJ Aero guy looks like he just made a closet with racks in his shop with insulating foam with some style of small heater inside. Making a mold adds cost which for one off things seems wasteful? I’m going to make molds for my bumper brackets. They are not THAT complex, but strength matters with them. They have to safely hold on a steel bumper for me (rules). So I want to vacuum bag them. Total weight for the seat back is 9.5 lbs. Tonight I have to glue the carpet to the back and screw the trim around the edges. Glued small wooded blocks inside for the screws to bite into last night and made aluminum mounts to replace the hinges.
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I'll take a factory appearing air cleaner assembly, bumper brackets, and dashboard. I'll pick them up next week.
 
Nice work.
I just got done replacing the rear seat in my 64 Barracuda.
Makes a good place for storage and almost stock looking.
 
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Well, it’s done. Have to paint the mounts black and install it. 9.5 lbs total. 40 lbs less.
 
furrystump said:
View attachment 1715959019 View attachment 1715959021 Well, it’s done. Have to paint the mounts black and install it. 9.5 lbs total. 40 lbs less.
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Good idea!! I bracket race my 92 D150 on occasion and just took out close to 100 lbs. by taking out the heavy floor mat that covered the bed floor and by taking out the heavy spare the result was lower E.T.s checking my log book it looks like I picked up around a tenth even in not so good air.
 
Rule of thumb I have heard thrown around is 1/10 per 100 lbs.
 
Thought about the dash, but you have to remove the windshield to get it out.
 
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