Resin hoods

[Immortal Chips]

Hi all, just after some advice. I've used these hoods in the past and also just received a new lot for future builds but the resin hoods never fit well. I've tried reshaping them by trying to heat them and set them back into place but its very difficult to get them perfect. Ive ordered them from Competition Resins and their stuff is good but the hoods also seem to be an issue. Does anyone else have any advice or tips on how to get the hoods to fit properly?

I've supplied some pics for reference.

Thank you for your help.

[MrObsessive]

I'm no expert as resin, but I can tell you that my experience has been that when you heat up resin (hot water, hair dryer, etc.), it's best to immediately lock the shape into place by putting it in cold water. Also contrary to popular belief, resin does have a memory, so it's also a good idea when you're washing the parts, to NOT use hot water again as guess what??.............the resin will go back to the shape that it originally wanted to be ie: slightly warped.

I'd use very lukewarm or cold water to wash things up.

I would also paint both sides of the hood so that the solvents won't pull one side away from the other-------not doing so can lead to the same type of warp you're seeing. 

Hope this helps as that can be frustrating........others may have different methods to help out.

[mikemodeler]

Have you contacted the resin company? Something that is obviously that far off and is basically unusable should be brought to their attention.

You might be able to make your own hood using styrene and the kit hood, have you considered that?

[Immortal Chips]

I'm no expert as resin, but I can tell you that my experience has been that when you heat up resin (hot water, hair dryer, etc.), it's best to immediately lock the shape into place by putting it in cold water. Also contrary to popular belief, resin does have a memory, so it's also a good idea when you're washing the parts, to NOT use hot water again as guess what??.............the resin will go back to the shape that it originally wanted to be ie: slightly warped.

I'd use very lukewarm or cold water to wash things up.

I would also paint both sides of the hood so that the solvents won't pull one side away from the other-------not doing so can lead to the same type of warp you're seeing. 

Hope this helps as that can be frustrating........others may have different methods to help out.

Hi Bill, thanks for the tips, I'll give it ago

[Immortal Chips]

Have you contacted the resin company? Something that is obviously that far off and is basically unusable should be brought to their attention.

You might be able to make your own hood using styrene and the kit hood, have you considered that?

Hi, I did email them but I'm yet to receive a reply, ive never tried to make my own cowl hood but might try it out in the future, thanks 

[69NovaYenko]

I have purchased parts from that same resin caster in the past and overall they make great stuff. True, a bit of twinkling may be in order to get a resin part to fit properly but no one should have to pay for something that you have to wrestle that badly with to fit.  Come on people, anything that is that badly misshapen should be replaced by the vendor or your money should be refunded IMHO. Is having resonable expectations that the product/service should meet reasonable and exceptable standards a thing of the past?

Edited March 28, 2016 by 69NovaYenko

[espo]

I have had very mixed results with resin cast parts and bodies. In to many cases its just more trouble than its worth, What I did do on a resent build that I wanted a cowl hood for was use the hood from the '69 Nova SS. I cut the cowl portion of the hood and cut out the center of the hood for a '66 Impala build. The hoods are the same thickness which helped and only used minimal filler. I would suggest you try making your own, and if it turns out the way you want then cast it your self for the future.   

[Immortal Chips]

I have purchased parts from that same resin caster in the past and overall they make great stuff. True, a bit of twinkling may be in order to get a resin part to fit properly but no one should have to pay for something that you have to wrestle that badly with to fit.  Come on people, anything that is that badly misshapen should be replaced by the vendor or your money should be refunded IMHO. Is having resonable expectations that the product/service should meet reasonable and exceptable standards a thing of the past?

I agree Greg!

[Immortal Chips]

I have had very mixed results with resin cast parts and bodies. In to many cases its just more trouble than its worth, What I did do on a resent build that I wanted a cowl hood for was use the hood from the '69 Nova SS. I cut the cowl portion of the hood and cut out the center of the hood for a '66 Impala build. The hoods are the same thickness which helped and only used minimal filler. I would suggest you try making your own, and if it turns out the way you want then cast it your self for the future.   

Hi David, thanks for the tip

[louie]

Hi all, just after some advice. I've used these hoods in the past and also just received a new lot for future builds but the resin hoods never fit well. I've tried reshaping them by trying to heat them and set them back into place but its very difficult to get them perfect. Ive ordered them from Competition Resins and their stuff is good but the hoods also seem to be an issue. Does anyone else have any advice or tips on how to get the hoods to fit properly?

I've supplied some pics for reference.

Thank you for your help.

I am sorry for saying this but that is absolutely terrible. I can't believe how bad that hood is. You should not have to put up with that. You paid good money for it, you should get a good product for it. I can understand some clean up but that's going a bit further than some cleaning up on that hood. Sorry for my rant but I am on your side about this.   Thanks.    Jeff 

[64SS350]

I make my own by simply adding a WRP brand cowl to my existing hood. They usually run like $5 for a pair.

 

 

[Immortal Chips]

I am sorry for saying this but that is absolutely terrible. I can't believe how bad that hood is. You should not have to put up with that. You paid good money for it, you should get a good product for it. I can understand some clean up but that's going a bit further than some cleaning up on that hood. Sorry for my rant but I am on your side about this.   Thanks.    Jeff 

Thanks Jeff I agree 

[Immortal Chips]

I make my own by simply adding a WRP brand cowl to my existing hood. They usually run like $5 for a pair.

 

 

Thanks for the tip Karl 

[Lunajammer]

 

This might be salvagable if you have some time. Looks to me like it might have been cast okay, but stored poorly. Resin will warp if pressure is placed on it over time. Even being in a tight bag might do this. Looks like it flattened out. Sounds like you know to try sticking it in hot water to soften it up, counter-warp it by hand, stick it into place in your model, tape it down and leave it there a long time... like a month or two. It may find it's way back.

Some white resins remain pliable for weeks if not mixed perfectly. If it was bagged while still pliable, then set that way, you may be out of luck. Either way, the caster should make good. Your photos pretty much tell the tale.

 

[Mark]

The shape of the hood (the cross-section) combined with the (infinitely minor) shrinkage of the resin are probably the cause.  I've got two copies of a particular hood, made years apart by two different casters.  Both have this same problem.

With my hoods, the part is thinner at the edges, heavier in the middle (scoop area).  This hood is of relatively consistent thickness, but the scoop is at the center and it uses quite a bit of material compared to the relatively straight outer portions.  The resin doesn't shrink very much, but when it does shrink it is doing so across the entire length/width of the part.  The scoop area, whether thick as on my hoods, or thin and relatively large as on this hood, is shrinking more than the outer portion because it has more material.  That appears to be what is pulling up the corners of the hood.  I've forgotten a fair amount, but have cast enough different part shapes to figure out which shapes are likely to be problematic.  Had the hood been cast as two pieces (hood with hole, and separate scoop) or maybe three pieces (center section with scoop/forward portion of hood ahead of the scoop, and two outer pieces) there would still be the same amount of shrinkage (which isn't even measurable, really).  The separate pieces would fit together and the assembled hood wouldn't have that curling problem at the corners.

Is the center/top of the scoop sinking in too?  The rear edge of the scoop appears to be straight, as does the forward part where the scoop transitions down to the level of the hood.  That makes sense to me as the rear edge has the two sides to shore it up, while the curvature at the front lends strength to that area.  The closest comparison to this would be casting a four-sided piece (like a box but missing the top and bottom surfaces).  The sides will all pull in towards the center because, towards the corners, each side has the corner to strengthen that area.  In the middle, there's nothing to shore up the side, so it will pull in a bit. 

[Immortal Chips]

The shape of the hood (the cross-section) combined with the (infinitely minor) shrinkage of the resin are probably the cause.  I've got two copies of a particular hood, made years apart by two different casters.  Both have this same problem.

With my hoods, the part is thinner at the edges, heavier in the middle (scoop area).  This hood is of relatively consistent thickness, but the scoop is at the center and it uses quite a bit of material compared to the relatively straight outer portions.  The resin doesn't shrink very much, but when it does shrink it is doing so across the entire length/width of the part.  The scoop area, whether thick as on my hoods, or thin and relatively large as on this hood, is shrinking more than the outer portion because it has more material.  That appears to be what is pulling up the corners of the hood.  I've forgotten a fair amount, but have cast enough different part shapes to figure out which shapes are likely to be problematic.  Had the hood been cast as two pieces (hood with hole, and separate scoop) or maybe three pieces (center section with scoop/forward portion of hood ahead of the scoop, and two outer pieces) there would still be the same amount of shrinkage (which isn't even measurable, really).  The separate pieces would fit together and the assembled hood wouldn't have that curling problem at the corners.

Is the center/top of the scoop sinking in too?  The rear edge of the scoop appears to be straight, as does the forward part where the scoop transitions down to the level of the hood.  That makes sense to me as the rear edge has the two sides to shore it up, while the curvature at the front lends strength to that area.  The closest comparison to this would be casting a four-sided piece (like a box but missing the top and bottom surfaces).  The sides will all pull in towards the center because, towards the corners, each side has the corner to strengthen that area.  In the middle, there's nothing to shore up the side, so it will pull in a bit. 

Hi Mark, thanks for your reply, the hoods appear to have flattened out or even starting to curve too much the opposition direction rather than curve in to shape with the body and sit flush. The only way I have been able to make them fit is by heating and clamping them back into shape ( slightly more than needed to allow for recoil) and hoping they fit but it's very difficult to get them perfect as if not you need to repeat the process again. I believe these hoods should fit better than that when casting and not need to be reheated and reshaped to fit correctly. Thanks Nick 

[CelticModeler]

I make my own by simply adding a WRP brand cowl to my existing hood. They usually run like $5 for a pair.

 

 

where did you get these? And what do you use for filler to make it seamless to the hood. I looked them up but only find pics of hoods in bags and cant see what they actually are. If you have a build thread showing how you install them id love to see it.

[64SS350]

I get mine from my local slot car track. The PU is plain, the Impala I modified with a file and sanding to achieve the inset line. They come packaged in pairs,you can cut them down to different heights and lengths to fit your hood. I use either Bondo putty, glazing, and the green modeling filler.

If you need more ideas to do these, maybe I could do a thread on installing one.

Hope this helps...Karl

[CelticModeler]

I get mine from my local slot car track. The PU is plain, the Impala I modified with a file and sanding to achieve the inset line. They come packaged in pairs,you can cut them down to different heights and lengths to fit your hood. I use either Bondo putty, glazing, and the green modeling filler.

If you need more ideas to do these, maybe I could do a thread on installing one.

Hope this helps...Karl

that would be awesome. Trying to make one on my 70 camaro and cant come up wIh anything