Ski Builders Forum

I wouldn't personally use gorilla glue on sidewalls either, but that's all personal preference. I use the same epoxy that I do for the layup. I don't heat it at all, but I let it cure for a few days at room temp before doing any profiling (I use supersap).

I wasn't asking about the masking tape repair, there are a few small pieces of masking tape under your topsheet holding the tip spacer in place. Don't do that anymore, if you are still doing it. Do a search for "medipore tape". It's a porous medical tape, that soaks up epoxy nicely. Masking tape inside the ski may cause delamination (and you mentioned you had some delam, so that could be a culprit, although there is probably more at play too if the entire topsheet delammed up there).

Are you flaming your top sheets prior to layup? How about your tip spacers? All plastics should get flamed, preferably close to layup (I do it all minutes before layup)

As for sidewalls being a mess - yeah... big mess. I gave up trying to protect my clamps, I use the same blue Irwin clamps and they are covered in old epoxy. The clamps still all work fine, if it gets on the steel bar, the clamp will usually pop the epoxy right off as you tighten it. Just looks ugly. Just make sure your protect whatever is under the core, you don't want epoxy on your floor!

Are you flaming your top sheets prior to layup? How about your tip spacers? All plastics should get flamed, preferably close to layup (I do it all minutes before layup)

Thanks for the advice twizz I do the same thing and use supersap for my sidewalls.

But I buy all my materials from the skilab as they are pretty close to me and they say all their materials are sanded and flamed. Do I need to flame them again right before layup?? I usually only flame and sand my sidewalls right before layup.

Funny, Kam used to live near me (in Seattle), but moved a while back.

I still flame everything, regardless of if its been flamed. I don't think Kam is flaming anything he sends out, it comes pre-treated from the manufacturer. It's probably been a long time since it was flamed!

Preventing delam often comes down to surface preparation - cleanliness and flaming are your friends (but you don't want to over-flame either... it's an art, and many/most of us don't really know what we're doing... whatever we're doing works for us so we keep at it)

(I fixed your quote formatting in your previous post )

By hardwood backer I mean I bond my sidewall material with epoxy to a 6mm thick ash hardwood. This gets ripped into 13 mm strips and glued directly to the shaped cores.

Ah ok. I thought it was some sort of double sided tape, which I have though of using. Maybe like that pressure sensitive tape or carpet tape maybe. ??

Preventing delam often comes down to surface preparation - cleanliness and flaming are your friends (but you don't want to over-flame either... it's an art, and many/most of us don't really know what we're doing... whatever we're doing works for us so we keep at it)

I feel like just sanding instead of flaming would be better because then it creates more imperfections for the epoxy to hold onto. You know when you buy the bike flat tire kits and they say to sand the inner tube to aid in the adhesion of the patch. Maybe something along those lines.


Also what do you guys use for flaming? I just use a cheap benzomatic blow torch from home depot. With that it is a very time consuming process to flame my sidewalls, so I can only imagine how long it would take to flame my topsheets and bases. Any other methods??

Flaming all plastics is essential to preventing delams.

Read this article for details on flaming process.

http://www.westsystem.com/ss/gluing-pla ... lex-epoxy/

direct quote from the article
"To flame treat a plastic surface, hold a propane torch so the flame just touches the surface and move it across the surface at a rate of 12 or 16 inches per second. Keep the torch moving and overlap the previous pass slightly. When done correctly, the surface will not discolor or burn in any obvious way. This technique oxidizes the surface and improves adhesion. For best adhesion, bond to the surface within 30 minutes of treatment."

what you want to see is this when you drop a water drop onto your plastics.
high edge angles are bad, low edge angles are good and indicate a better surface for bonding.

thank you so much vinman!! that clears up so many questions I had on the flaming proccess,

Sanding alone without flaming may make things worse. It only takes a few minutes to do everything with a propane torch, you don't hold the flame in one place for very long. The water test works great (just make sure its all dry before you start layup )

I usually pre-test, do 4 passes per sidewall, retest and usually 2-4 more witha final test checking for a flatter drop shape. 8 passes per sidewall on both sides is my usual. The drop shape flattens signficantly after 4-6 passes.

Ok so last night I was profiling my cores with my router bridge and had a snafu with the router, so now I have a huge trough in the tail of my ski. When I flex it, it acts like a hinge point and I can see it being a possible break point for the ski. The trough is on the top of the core.

How do i fix this????

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New core, no fixin that.

also you need to identify the problem and fix it before making another core. Rebuild the bridge if you have to. Otherwise you could have same problem again.

I fixed the issue on the router bridge with my next core, which is much better. However I don't have enough material for a new core, soooo how do I fix this issue with the flex ?? Maybe I could glue some veneer in ?? or use some Fiberglass?? Or when I lay it up add a patch of glass there??

What thickness were you aiming for and what thickness is it at the stuff up point?