Fiberglass body kit install?

B

bridgeport13b

Hi guys need some help on a body kit install. I am putting a wide body kit on a Mazda rx7, anyways the oem metal arches are cut out to fit bigger tires since it has a gm ls3 in it. What I want to know is the proper way to make sure that I don’t have any issues with rust and weather or not I should build another lip on oem quarter panel that meets up to the fiberglass panel so that I can put panel bonding adhesive and make it very strong. I started making a new lip just so you guys can see what I mean.
Thanks Richard
 

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Here is pics of the lip I mocked up to meet up to fiberglass arch. I was going to seal everything in with 3m panel bonding adhesive.
 

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As we discussed, your plan is good.
After panel bond spray or brush epoxy over the bare metal that is left.
Clean welds good first.
 
As we discussed, your plan is good.
After panel bond spray or brush epoxy over the bare metal that is left.
Clean welds good first.
Hey Barry that’s what I’m going to do, but what I’m really trying to figure out is if I should build a sheet metal arch to secure the new wheel arch
 
I see no reason to build anything to bond the new fiberglass panel on as long as the new fiberglass panel has a surface to completely attache to. Glue it on and seal it with epoxy and your good to go.
 
I see no reason to build anything to bond the new fiberglass panel on as long as the new fiberglass panel has a surface to completely attache to. Glue it on and seal it with epoxy and your good to go.
The lip area does not have any bond area, dirt and water can get between panels, that’s why I built a new lip to attach the fiberglass panel to it.
 

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Well, that's got all the potential to rust and crack down the road... The maker of the body kit, they have any instructions? Is it not a by the book install because you had to cut the wheel arches for bigger tires? Pics of the fiberglass kit may help.
 
Well, that's got all the potential to rust and crack down the road... The maker of the body kit, they have any instructions? Is it not a by the book install because you had to cut the wheel arches for bigger tires? Pics of the fiberglass kit may help.
Why would it rust and crack? Dissimilar materials? There are no instructions. Most people cut the arch on oem quarter and weld the inner wheel house to the outer quarter panel which raises it 1 1/2in. Also that method leaves a gap between
 
Pics
 

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You're doing right by sealing the gap, and making sure ALL the metal is covered with epoxy. I've never personally seen a body kit that didn't crack, no matter what steps were taken. Metal and fiberglass are like oil and water, and will separate eventually, IMO
 
I've never seen a quality fiberglass body kit.:mad: Put a widebody kit on a Civic about 15 years ago that just about made me quit my job.

As for your question Bridgeport, do as Texas says and cover all metal with epoxy, brush it on the backside if you have too. Seal the gaps. Use a 2 part seam sealer.
 
I've never seen a quality fiberglass body kit.:mad: Put a widebody kit on a Civic about 15 years ago that just about made me quit my job.

As for your question Bridgeport, do as Texas says and cover all metal with epoxy, brush it on the backside if you have too. Seal the gaps. Use a 2 part seam sealer.

You're doing right by sealing the gap, and making sure ALL the metal is covered with epoxy. I've never personally seen a body kit that didn't crack, no matter what steps were taken. Metal and fiberglass are like oil and water, and will separate eventually, IMO

Hi I bought 3m panel bonding adhesive and 3m seam sealer both are two part. I will spray it with spi epoxy to ensure corrosion protection. Back side is not really accessible which is why I bought 3m cavity wax and there wand kit. Appreciate all the help. I started grinding the welds on the new lip and hope to get it in epoxy in a few days. Also if I do decide to use abrasive blasting as a means to scuff the welds up what media to use? Soda?
 
A few things here. 3-m 8115 adhesive or equivalent can give a strong crack resistant bond and where it covers bare metal it will keep rust out. Bonding edges of bare metal need to be sanded coarse for good adhesion. Contact area around perimeter to be glued needs to be a decent width for glue to be able to do it's job.
Though epoxy will bond fiberglass to steel, they will expand & contract at different rates which in some cases can cause harsh shadowing in the future. If a fiberglass part has a bit of an intersecting angle creating a bodyline, it can mask the shadowing effect pretty good. If a fiberglass part has to lay flat & blend into a steel panel, (top of your part it looks like) that will more likely than not shadow. A filler such as SEM carbo fill as the base coat of body filler can minimize this effect.
Some fiberglass kits are better than others, average ones for imports probably aren't near the greatest quality. That said, with any fiberglass parts, your best friend is to let the parts get at least a few days minimum of hot sun after bonding on before final bodywork. The lesser quality parts can shrink a lot in the first few weeks.

An option for the wheelwell portion of the bond, which won't be highly seen, but gets the most stress, would be to use a commercial urethane caulk/ sealant instead of the stiffer more likely to crack epoxy. Using a caulk at my day job past couple of years from tremco called Dymonic. It's passed several personal stress tests I've put it through on metal to metal & metal to fiberglass. Will be using in wheel well to quarter panel bond on my steel widebody project. Cheap enough to use a lot more of it to ensure coverage & a wider bonding area. Yea, not traditional automotive product, but I think you just heard enough opinions about traditional stuff sucking.
https://www.tremcosealants.com/fileshare/DataSheets_Hyland/Dymonic_100_DS.pdf
 
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Hi I bought 3m panel bonding adhesive and 3m seam sealer both are two part. I will spray it with spi epoxy to ensure corrosion protection. Back side is not really accessible which is why I bought 3m cavity wax and there wand kit. Appreciate all the help. I started grinding the welds on the new lip and hope to get it in epoxy in a few days. Also if I do decide to use abrasive blasting as a means to scuff the welds up what media to use? Soda?

No. Zero need for that. Soda brings a fresh set of issues that you would need to deal with (neutralizing it before applying epoxy) Use a black "cookie" roloc disc or something similar.
 
No. Zero need for that. Soda brings a fresh set of issues that you would need to deal with (neutralizing it before applying epoxy) Use a black "cookie" roloc disc or something similar.
Ok
A few things here. 3-m 8115 adhesive or equivalent can give a strong crack resistant bond and where it covers bare metal it will keep rust out. Bonding edges of bare metal need to be sanded coarse for good adhesion. Contact area around perimeter to be glued needs to be a decent width for glue to be able to do it's job.
Though epoxy will bond fiberglass to steel, they will expand & contract at different rates which in some cases can cause harsh shadowing in the future. If a fiberglass part has a bit of an intersecting angle creating a bodyline, it can mask the shadowing effect pretty good. If a fiberglass part has to lay flat & blend into a steel panel, (top of your part it looks like) that will more likely than not shadow. A filler such as SEM carbo fill as the base coat of body filler can minimize this effect.
Some fiberglass kits are better than others, average ones for imports probably aren't near the greatest quality. That said, with any fiberglass parts, your best friend is to let the parts get at least a few days minimum of hot sun after bonding on before final bodywork. The lesser quality parts can shrink a lot in the first few weeks.

An option for the wheelwell portion of the bond, which won't be highly seen, but gets the most stress, would be to use a commercial urethane caulk/ sealant instead of the stiffer more likely to crack epoxy. Using a caulk at my day job past couple of years from tremco called Dymonic. It's passed several personal stress tests I've put it through on metal to metal & metal to fiberglass. Will be using in wheel well to quarter panel bond on my steel widebody project. Cheap enough to use a lot more of it to ensure coverage & a wider bonding area. Yea, not traditional automotive product, but I think you just heard enough opinions about traditional stuff sucking.
https://www.tremcosealants.com/fileshare/DataSheets_Hyland/Dymonic_100_DS.pdf
The fiberglass panels I have are actually very high quality and fit perfect. They are a fiberglass panel and have a carbon fiber back to them to make them stronger. They are a replica from a company in japan that makes them. The two rear panels are pretty damn expensive, and have very good reviews from the Mazda groups. Also I will be keeping the upper body line but will blend in rear seam and front seam on rocker. Also in regards to body flex cracking the panels, the chassis does have chassis stiffeners throughout and will have a rear cage. Chassis is extremely rigid, I can lift front up with engine from rear lol there is absolutely no flex. Only thing that would cause cracks is wheel contact and there is very good clearance
 
Why would it rust and crack? Dissimilar materials? There are no instructions. Most people cut the arch on oem quarter and weld the inner wheel house to the outer quarter panel which raises it 1 1/2in. Also that method leaves a gap between

No problem with dissimilar metals. I'm just seeing lots of edges and holes that at first glance make me think rust. If you address them well as you're planning it should be ok. Do pay close attention to gaps and inaccessible areas that could hold dirt and water. On post 7 pic 4, that lip that's turned up vertical, if the glass panel comes down to touch that, there will be a large open area behind it correct? Just be sure to prep and coat the hell out of it before closing it up. Also how will you attach the glass to that vertical lip? If it had a flat or horizontal bend there you could bond directly to it and be very strong. It could buzz or rattle if that edge is in contact with the glass panel. Am I on the right track? I could be missing something... :)
The kit looks goo btw... Not ghetto at all, tastefully done.
 
No problem with dissimilar metals. I'm just seeing lots of edges and holes that at first glance make me think rust. If you address them well as you're planning it should be ok. Do pay close attention to gaps and inaccessible areas that could hold dirt and water. On post 7 pic 4, that lip that's turned up vertical, if the glass panel comes down to touch that, there will be a large open area behind it correct? Just be sure to prep and coat the hell out of it before closing it up. Also how will you attach the glass to that vertical lip? If it had a flat or horizontal bend there you could bond directly to it and be very strong. It could buzz or rattle if that edge is in contact with the glass panel. Am I on the right track? I could be missing something... :)
The kit looks goo btw... Not ghetto at all, tastefully done.
Yeah your right about the lower edge, trying to figure out what I should do about it. It’s kind of hard to work around but I have a few ideas one being just to scuff it up and fill with epoxy or extend the lip. If I extend the lip then I will have the lip so close to the oem quarter panel that I may not be able to scuff and paint that area. So I may just have to fill that area with bonding adhesive or something similar.
 
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