I think the comments are directed at the amount of space between the plugs and the top of the foam post in the H pattern. See my red circle on your photo. In my opinion, the distance from the top of the foam post and the bottom of the plug should be much less than what is shown. As you see this leads to a rather large resin pool and more exotherm. As a side note, the epoxy/milled fiber mixed is strong enough to compensate for this type of install problem as the foam post adds virtually no strength to the H pattern install. The foam post is really just a low density filler for the epoxy/milled glass tube extending to the deck, but the air bubble under the plug may lead to leakage issues or collapsing of the deck side glass.
I can’t tell from your pictures whether there is a problem in the blue box area as well. And this is the area where real strength issues occur.
You have labeled these as failures and I would agree with that in general, but it looks more like an install oversight that produced an exotherm failure. Our experience has shown that with the plug/post distance kept to minimum, using about 20% milled fiber by weight in our slow hardener (aka fin juice)/resin, that this type of exotherm failure does not occur. We have several hundred boards of field experience with this install and no failures. The downside of using slow, low exotherm systems is of course a longer wait until the plugs can be ground down.
I can certainly understand that you would want a totally fool proof system for an install, but for that to happen you still need attention to the small details on the install for complete success. Please feel free to correct me if you think I have overstated anything here.
Rob
ps I have some samples coming to you to look at for the extreme situations that we talked about on the phone.
I think the comments are directed at the amount of space between the plugs and the top of the foam post in the H pattern. See my red circle on your photo. In my opinion, the distance from the top of the foam post and the bottom of the plug should be much less than what is shown. As you see this leads to a rather large resin pool and more exotherm. As a side note, the epoxy/milled fiber mixed is strong enough to compensate for this type of install problem as the foam post adds virtually no strength to the H pattern install. The foam post is really just a low density filler for the epoxy/milled glass tube extending to the deck, but the air bubble under the plug may lead to leakage issues or collapsing of the deck side glass.
I can’t tell from your pictures whether there is a problem in the blue box area as well. And this is the area where real strength issues occur.
You have labeled these as failures and I would agree with that in general, but it looks more like an install oversight that produced an exotherm failure. Our experience has shown that with the plug/post distance kept to minimum, using about 20% milled fiber by weight in our slow hardener (aka fin juice)/resin, that this type of exotherm failure does not occur. We have several hundred boards of field experience with this install and no failures. The downside of using slow, low exotherm systems is of course a longer wait until the plugs can be ground down.
I can certainly understand that you would want a totally fool proof system for an install, but for that to happen you still need attention to the small details on the install for complete success. Please feel free to correct me if you think I have overstated anything here.
Rob
ps I have some samples coming to you to look at for the extreme situations that we talked about on the phone.
Hey Rob-
Thanks for your comments. I can assure you those were not install oversights. The posts were fully intact in all of the test samples we used prior to pooring in the resin and those particular posts were melted by the exotherm, therefore resulting in the extra distance between the bottom of the plug and what remains of the post. To answer your question, there is a problem with the side walls in the blue box you showed which does sacrifice the strength and integrity of the install and system. Here’s a photo of a clean one where there were no problems for comparison.
I appreciate you throwing it out there, but I can assure you the small details of the installation were not overlooked in our testing.
Thanks for the response. My initial thought was that your were showing a worst case install scenario. Sorry if I misunderstood. This picture from your last post is what we saw in our trials and what I believe can happen on a daily basis in most shops.
I will take a second shot at emphasizing that people should be using more milled fiber (NOT microballons) than they are used to (20% by weight seems the best) in epoxy.
BTW neither of these have a FCS plug at the top, so it is a 3/4 inch solid mass of resin or resin/fibre at the top of a typical H pattern.
The inserts do come supplied with Fusion and they are pre-bonded. As you suggest, it is a quick and easy install. The insert is 1/2" thick (12.7mm) and the bottom of the plug and bottom of the insert are flush. Here’s a side view and bottom view for a better perspective:
Side View:
Bottom View:
You are right about milled fiber. In our testing we found that adding more milled fiber than normal definately helped with the exotherm issue, but the more you add, the thicker the mixture gets and is a little hard to work with. Also you then run the risk of the mixture being too brittle once cured. Thanks for your comments and open mind and let me know if any additional questions.
To ScottC-
I’m not sure if maybe you are getting traditional FCS and Fusion confused? Just to be clear, no routing was done with these test samples. Only drilling. The view you are looking at in my previous pictures is a side view showing what we like to call the “H Pattern”. Check out my last post to Rob W for a comparison pic of one that had no problems. The skinny line of resin that you see does provide the strength of the system as a column encasing and connecting the plug with the deck of the board. On the subject of Fusion, which is totally different than traditional FCS (which was in my previous pictures), I agree with your equation: tight route = no pools of resin = no exotherm problems. This is why we made Fusion this way.
To Surfer Dave- Our new X-2 plugs are not made of UHMWPE, but instead a proprietary blend of nylon and fiberglass that we worked on with Dupont. Unfortunately I can’t disclose the material we use for Fusion with respect to IP. I can tell you we tested a few different material options and the one we went with performed the best in our testing in terms of strength, bonding and ease of sanding.
thanks, you mentioned nylon and fiberglass, you mean fiberglass as in the strands or the general usage of the term fiberglass to include polyester resin? The latter would make more sense to me but I am aware of dupont’s activities with nylon and fiberglass with regards to the carpet industry. Anyway, ok, if it’s all shush shush, just curious about the engineering side of it.
is what we saw in our trials and what I believe can happen on a daily basis in most shops.
