TWINRAY

Seems the trend for bonding front end pieces on is an Epoxy type - either a Fusor product, 3M or a "Marine" type. When this type of product is used, I would think future individual panel replacement seperation (in the event of a accident etc.) would be nearly impossible. OTOH, a "Bonding Adhesive" (like used oem) makes panel seperation probable, though difficult. Sermersheim seems to make a adhesive similar to what was used oem. Ecklers does also but a poster had problems with that product. To those that have used epoxy based adhesives, I then assume you have no concerns about a maybe future needed panel replacement?

jnb5101

you bring up a good point, but what did the factory use on the sem panels? i think that any repair would involve cutting rather than separating.

TWINRAY

In my particular instance on my '69, my panels are "pre" SEM. I think SEM panels came after '72 or '73.

70BBvert

From personal experience both the fusor & 3M products I used softened & released after heating with a heat gun.

Jim

69 Chevy

TWINRAY

OK thanks - question answered

Easy Mike

SEM or SMC? SEM is good quality automative interior dye. SMC is sheet molded compound fiberglass. From 72 up, C3 bodies are SMC.

TWINRAY: I'm not sure what you want. After the whack, it isn't going to make much difference if the panels serparate or whether you have to spearate them. It's still going to be a mess.

jnb5101

sorry, mike. i had a sem-smc brain fart!
but, my point was that the newer smc panels are also replaced, so how is that done with the heat resistant adhesives?

0Willcox Corvette

I use SEM 39747 epoxy.. and for multiple reasons.

The stuff Sermershiem's sells is a great product and I used it for years. However you'd better know your horse before you ride it. The cure time is very fast and you'd better have every detail down before you use it. Changing the color of the hardener will not change the cure time either. For years Jim Sermershiem's had this in his book that one color would increase or delay cure.. Not true and Jim and I got in a debate about this to a point where I called the company that makes the hardener and they gave me the chemist... They all cure at the same rate the colors are made to offer varied colors to the glue. The hotter the temp the faster the cure..

The SEM epoxy is a slower curing product what will allow you way more working time. Slower cure time means less mistakes and a perfect installation. Application is way easier unless you use a cake decorator with the other stuff and even that isn't as fast as the Sem product that is ready to roll.

If properly scuffed before application you'll never have to worry about it coming loose.

Downfalls.. the gun to mix it with.. but if you have a friend who has a friend you can probably locate one.

Willcox

rogman16

Ernies--

I used the SEM 39747 when I bonded my front bumper and it worked like a champ... I was able to use my Fusor Gun for application...

Rogman

zwede

The Marine-Tex we used to bond the panels will release if heated with a heat gun. Found that out after I messed up the location of one of the exhaust filler panel braces.

0Willcox Corvette

The SEM will too.. the trick is to use a heat gun with two people... I have a tool I made years ago that will cut right through it and I guide and tap while someone else heats. But.. and it's a big one.. You must make sure the person running the heat gun doesn't burn the glass. You do this and nothing will bond to it.

E..

69 Chevy

My local auto paint supply store lent me their mixing gun overnight at no charge.

TWINRAY

Thanks all for the added info. I'll pick something that gives me a bit of time. Sure as heck don't want a gallon of the mixed stuff to start hardening while I'm in the middle of setting panels

Go Vette Go

I found the mixing gun on the WWW for $35 HERE
And the SEM 39747 was $27.49 per tube.

I got it delivered today and all looks good.

John

TWINRAY

Ok, I've decided to go with this stuff. Question - how many tubes will I need for a front end (top surround, bonding strips, 2 fenders, lower valiance and inner fenders.

Thanks, Fred

Go Vette Go

This probably will not help much Fred but I was told 2 tubes for the rear clip. So I bought 3.

John

70BBvert

I think I used 3 tubes of the 3M adhesive, but it's been a while. And I had less to bond. I'd have at least 4 on hand. You can always send it back. I bought from Fox Run tools, shipped right away and for free if over $99. make sure you get a compatible gun also

https://www.foxruntools.com/paneladh...ulti-purp.aspx

Jim

Maine Vette

I used epoxy adhesives almost exclusively when I did my body panel replacement. My overriding concern was fit-up time. When they built these cars on the assembly line they were tremendously efficient through the use of jigs and sheer repetition. As a result, they could fit up a body panel in no time. On the other hand, most folks working in their garage (myself included) work much slower. Depending on the temperature, with bonding compound you typically have 10-15 minutes to apply the compound, align the panel and secure it in place. It may sound like plenty of time, but it really isn't. For me the consequences of a potential mis-fit was a bigger consideration than future panel replacement.

Worst case scenario, future panel replacement would require grinding the body panel away down to the bonding strip. It's not a great solution, but it would allow panel replacement if needed.

I used Lord Fusor's 127 EZ and it had plenty of working time. I highly recommend it. I think I used about two tubes doing my one-piece front clip, inner fender skirts and front valence panel. If your using fusor (which I think comes in bigger tubes than SEM adhesive) I'd buy 3 tubes - better safe then sorry. You'll be some pizzed if you get half way through and find out your short on adhesive.

Solid LT1

You guys mean SMC (sheet molded composites) they first happened in the 73 model year from what I have been told.