Delmanation repair help needed

[greyhawk01]

Im repairing a delaminated side wall and im trying to find the best adhesive to glue the luan to the foam and filon. I was considering using 3m 30nf as an alternative to stabond which is extremely expensive. Has anyone used 3m and had good results. My second question is what kind of backer is used behind the filon on the front wall. It does not look like plywood it looks more like cardboard.

Thanks

[lane_hog]

I used 3M Super 77 (available at Menards, not sure about other big box DIY's), and it seems to have held up OK on a motorhome cab rebuild and again when I rebuilt the door a year later.

[Gjac]

larry cad wrote:

Gjac wrote:

3 tons wrote:
3 M Spray aerosol contact cement may help...At auto body supply vendors.

77N has been around for a long time, and I have bonded many panels for aircraft with it. You need good pressure to make it bond well. Other things to be aware of, sometimes it is almost impossible to dry the delaminated area if you don't have access to a garage, and the only adhesive that will work in that case is a polyurethane like Elmer's or Gorilla glue. The moisture will cause it to react with the glue and foam out. I made a mess bonding mine back together because I could not get all the moisture out. Acetone in the delaminated area will remove some of the moisture as it evaporates. Ideally if you have a dry area and urethane foam, not Styrofoam as a substrate I would use a good epoxy adhesive from west marine or another boat place. Another thing to know the glass transition temperature(Tg), the temperature in which the resin will begin to soften is much higher for epoxies because they are a thermoset resin. If parked outside in the sun in the summer a contact adhesive will soften from the heat. If you go with a contact adhesive check the spec sheet and see what the Tg is. I have not checked surface temperature on a hot sunny day in AZ in a parking lot but it would not surprise me if it got to 160 F. Hope this helps.

Certainly one of the best posts I've read on this forum in over 15 years. Well written and full of useful information.

Thanks for the kind words Larry. I worked for an aircraft company for 30 years and worked on a lot of composite development programs.

[larry_cad]

Gjac wrote:

3 tons wrote:
3 M Spray aerosol contact cement may help...At auto body supply vendors.

77N has been around for a long time, and I have bonded many panels for aircraft with it. You need good pressure to make it bond well. Other things to be aware of, sometimes it is almost impossible to dry the delaminated area if you don't have access to a garage, and the only adhesive that will work in that case is a polyurethane like Elmer's or Gorilla glue. The moisture will cause it to react with the glue and foam out. I made a mess bonding mine back together because I could not get all the moisture out. Acetone in the delaminated area will remove some of the moisture as it evaporates. Ideally if you have a dry area and urethane foam, not Styrofoam as a substrate I would use a good epoxy adhesive from west marine or another boat place. Another thing to know the glass transition temperature(Tg), the temperature in which the resin will begin to soften is much higher for epoxies because they are a thermoset resin. If parked outside in the sun in the summer a contact adhesive will soften from the heat. If you go with a contact adhesive check the spec sheet and see what the Tg is. I have not checked surface temperature on a hot sunny day in AZ in a parking lot but it would not surprise me if it got to 160 F. Hope this helps.

Certainly one of the best posts I've read on this forum in over 15 years. Well written and full of useful information.

[Gjac]

3 tons wrote:
3 M Spray aerosol contact cement may help...At auto body supply vendors.

77N has been around for a long time, and I have bonded many panels for aircraft with it. You need good pressure to make it bond well. Other things to be aware of, sometimes it is almost impossible to dry the delaminated area if you don't have access to a garage, and the only adhesive that will work in that case is a polyurethane like Elmer's or Gorilla glue. The moisture will cause it to react with the glue and foam out. I made a mess bonding mine back together because I could not get all the moisture out. Acetone in the delaminated area will remove some of the moisture as it evaporates. Ideally if you have a dry area and urethane foam, not Styrofoam as a substrate I would use a good epoxy adhesive from west marine or another boat place. Another thing to know the glass transition temperature(Tg), the temperature in which the resin will begin to soften is much higher for epoxies because they are a thermoset resin. If parked outside in the sun in the summer a contact adhesive will soften from the heat. If you go with a contact adhesive check the spec sheet and see what the Tg is. I have not checked surface temperature on a hot sunny day in AZ in a parking lot but it would not surprise me if it got to 160 F. Hope this helps.

[3_tons]

3 M Spray aerosol contact cement may help...At auto body supply vendors.

[greyhawk01]

Thanks for the help everyone. Does anyone know what material is under the filon on the front cap. It looks like cardboard. Im hoping I can find some sort of replacement at my local hardware store.

[dougrainer]

Any Water Based Contac cement will work 3M Contac 30 is what I used years ago. Just make sure any adhesive you use has NO PETROLEUM products as that will dissolve the foam and any styrofoam. Doug

[fourthclassC]

I have done a lot of delam repair and its been holding up fine for about 4 years now. I use gorilla glue only. Yes it bubbles out and needs to be trimed, but it is urethane based and waterproof. Also cheap.

[greyhawk01]

No it think the top corner of the roof was leaking. The prior owner had it resealed before I purchased it. I removed all the rotted wood. I will be starting with a clean surfaces on the foam and filon sides. I will put in new plywood and laminate back together and reseal. I dont want to do all this work and have it unglued in a few months because the adhesive failed. So i just want to get some opinions on adhesive from anyone who has done this before.

[Gjac]

How big of an area do you have? Is it directly below a window? Is the area that is delaminated dry now?

[BarneyS]

Moved to Tech Issues forum from DIY.

[ksg5000]

Might consider visiting a boat dealer - boats are similar to RV's without wheels and boats have more delam issue than RV's. Probably the best place to get legit delam advice.

[jdc1]

Weldwood contact cement