flickroll

flickroll

Well Known Member
I've decided to use the ClickBond nutplates for securing my -8's batwing wing tips. The ClickBond nutplate is bonded to the inside of the tip using ClickBond's epoxy adhesive. What is the best method for prepping a surface such as this for a bonding operation? Is there a mold release here that needs to be removed, and if so, how? Or will simply scuffing it up by sanding it with an 80 grit paper, followed by a wipe down with alcohol suffice? Thanks
 
Thanks for the quick response Mike. However this was more of a general question about bonding something to the unfinished side of polyester resin based fiberglass product. What's the best method of surface prep? Thanks
 
Anything stuck to cured epoxy or polyester resin will stick by mechanical attachment, rather than some funky chemical bonding process. So the surface you are bonding to should be well roughed up and clean. I rough with 60 grit, but 80 will do just fine. I would be amazed if there is any mould release on the inside of the wing tip (mould is on the outside :)), but giving it a good scuff will get rid of anything that is there. Wiping with alcohol, white spirit, or something similar should be get rid of any dust or other contaminant.

Pete
 
clean/scuff/clean

I'd clean soap and water first. After drying, clean with acetone, lacquer thinner. You can use coarse paper or, what I do is use my Dremel with sanding drum to scuff.

Clean with acetone again and you're ready to bond.
 
prepping Fiberglas

The way I understand both epoxy and polyester produce a residue on the surface as it cures (possibly as it ages also?) and that is referred to as wax by many. I always use lacquer thinner, MEK, or other solvent BEFORE I sand the surface, front side or backside, then, after cleaning, I scuff it with sand paper, 80 or so grit, wipe it down again with solvent then recoat or bond to it. If this process is followed and then allowed to sit over night before bonding I repeat the process it all over and I assume more wax has formed. I have never had any problems following this process and I have done two sets of cowls with wheel fairings and I make my own intersection fairings as well. The RV8 I am building will get the same treatment.

Dick DeCramer
RV6 N500DD flying
RV4 N149KC flying
RV8 fuselage
Northfield, MN
 
fiberglass bonding

epoxy laminates produce whats called amine blush. its water soluable so wash with warm water to remove it. however if a peelply was used(like on the inside of the cowl) the peelply will remove the amine blush when its stripped of the layup. so no water is needed. polyester resin is an air inhibited curing resin so the surface will always be tacky. when we want a finished surface with poly we put surfacing agent in the resin. which is basically a liquid wax that comes to the surface and seals it so it becomes tack free. to get a good secondary bond to either sand really well with 60 or 80 grit paper and wipe it clean with acetone. you should also use epoxy on epoxy and polyester on polyester to get the best bond. epoxy will bond pretty well on polyester but polyester wont bond for beans on epoxy. another tip when bonding epoxy onto aluminum like the front windscreen fairing. I wetsand the aluminum(80grit) with a little epoxy resin first then laminate on it. you'll get a way better bond to aluminum that way.
good luck happy building
Erik
 
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Welcome to VAF!!!!

Erik, welcome to the force!!

By your profile, seems you may become one of the composite "go to guys" here.

Good to have you here, how about some more info on your project??
 
flickroll said:
Thanks for the quick response Mike. However this was more of a general question about bonding something to the unfinished side of polyester resin based fiberglass product. What's the best method of surface prep? Thanks
Click to expand...

Looking rather quickly through the above linked site, I found this.

An in depth search of the above link may provide more info.

Good luck.
 
thanks 4 the welcome

my project is actually not mine. I am helping my dad build a RV7. I have worked in the composites industry for 20 yrs now. so i am doing all the fiberglass work on the project. and I'm also the goto rivet bucker;). so yes any fiberglass questions are more than welcome.
thanks again and happy building
Erik
 
Clickbond nutplates

One caution I have heard is that using a power screwdriver/drill on the screws going into the nutplates can heat them up enough to release the bonding.

flickroll said:
I've decided to use the ClickBond nutplates for securing my -8's batwing wing tips. The ClickBond nutplate is bonded to the inside of the tip using ClickBond's epoxy adhesive. What is the best method for prepping a surface such as this for a bonding operation? Is there a mold release here that needs to be removed, and if so, how? Or will simply scuffing it up by sanding it with an 80 grit paper, followed by a wipe down with alcohol suffice? Thanks
Click to expand...
 
Kellym said:
One caution I have heard is that using a power screwdriver/drill on the screws going into the nutplates can heat them up enough to release the bonding.
Click to expand...


Kelly, where did you hear that? With all of the screws in a wingtip a power driver of some sort is just about a necessity.
 
prepping Fiberglas

The way I understand both epoxy and polyester produce a residue on the surface as it cures (possibly as it ages also?) and that is referred to as wax by many. I always use lacquer thinner, MEK, or other solvent BEFORE I sand the surface, front side or backside, then, after cleaning, I scuff it with sand paper, 80 or so grit, wipe it down again with solvent then recoat or bond to it. If this process is followed and then allowed to sit over night before bonding I repeat the process it all over and I assume more wax has formed. I have never had any problems following this process and I have done two sets of cowls with wheel fairings and I make my own intersection fairings as well. The RV8 I am building will get the same treatment.

Dick DeCramer
RV6 N500DD flying
RV4 N149KC flying
RV8 fuselage
Northfield, MN
 
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