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Old Mar 30, 2004, 08:39 PM
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Tachikaze's Avatar
United States, OR, Eugene
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Fiberglassing Problem

Ladies and Gentleman,

I am having problems with a boat that I am trying to fiberglass. At the time that I glassed the boat in question, I glassed another boat at the same time. The boat with the problem is Los Angeles Fireboat #2. It is their new Voith Drive boat, same boat as Umi is building. The other boat, that is not having a problem is the HIJMS Shimakaze, a WWII heavy destroyer. Both were done on the same day, using the same technique and same epoxy resin.
Here is the problem. On the bottom of the keel of the fire boat( which is a flat surface and facing up as the boat is left to dry) there are spots where the resin is still soft and sticky. These spots were too large to sand out as they would gum up the sand paper. The Shimakaze had non of these problems. Both boats were prepped the same way and constructed out of the same balsa wood. The only differnence that I would percieve is that the Shimakaze has a round surface when placed keel up to dry.
Not wanting to spend all my time cutting up pieces of gummy sand paper, I took a blade and cut out the soft spots to where there was no soft areas that I could cut out with an xacto blade. What this did was create areas of indentation where the soft resin was cut out and there would be a sticky bottom to these spots. The largest spot would be about 4x3cm.
I then came back and reglassed the entire boat hull with a differnent brand of epoxy resin. It was percieved that the brand that I had used was old, it was perhaps 2 years on the shelf after having been opened.
All seemed well, the glass job looked good. That is until the finishing touches. I used Kyron spray paint to prime the boat to evaluate for defects. I sanded this out and then appiled Deft Sanding Laquer to make the finishing touches before another primer coat.
There are now several areas where there is a blistering or wrippling of the surface. Sanding of this demonstrates soft resin again. I have now cut these out as I had done before, and it appears as if I am back to where I was before. The areas seem to be at the same depth as before and in the same general area. It is as if what ever was under the last glass attempt, worked its way up through the last glass attempt, unless I sanded down to that level. But I do not percieve that I did sand down through the last layer of glass to expose this soft area.
I do not recall what the first resin was. It was a blue container that I had obtained from TAP plastics with a small bottle of activator. The last layer was from TAP plastics and it was two container of equal volume between resin and hardener. It is the red and the beige containers.
Any ideas as to what to do to fill these defects and be able to finish off the hull? All areas not affected ( that vast majority of the boat) looks fine.
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Old Mar 30, 2004, 09:28 PM
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Albuquerque NM
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Tach, I had a similar problem with a cowl I made a few years ago. It turned out that the problem was caused by an oily substance that had been accidentally splashed on the mold. I thought I got it all out ,but aparently there was still a bit of residue soaked into the mold.
The solution was to cut away the effected ares (as you've already done once) and fill those areas with Bondo automotive body filler and sand everything back to level, then, rub the surface with a paint prep degreaser and wax remover. The primer still fish eyed in several spots, but a continuouse re-clean and re-prime ultimately ended in success.
I hope this helps, and believe me, I understand how it feels to get bitten like this, but it should work out OK, though not without a fair amount of extra effort.
PAT
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Old Mar 31, 2004, 02:30 AM
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Pat's suggestion echos what I was going to say.

The other possibility I suppose is that the wood itself has a resinous content which leeches through. I had that problem with a pine hull years ago. At that time I used polyester resins (I now only use epoxy). I finally went to a local company to ask their advice. They told me that the hardener was unstable and should be used fresh - shelf life of 6 months max. It was also fugitive, and would seek out any organic material and combine with it - the resin in the wood. This not only softened the resin but also lowered the %age of resin/hardener so it would not work as it should. As I always use a sealer on the surface before glassing, I had thought that would be sufficient but of course that was organic too......

I hesitate to suggest it, but I assume you gave it a good mix and left it for a few minutes before use?
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Old Mar 31, 2004, 07:23 AM
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Rsins

Tony, Back in those days I was still using "hobby quality" resins, which I don't do anymore. I'll still glue things together with it, but for fiberglass work, the only thing I use now is West Systems epoxy resin.
I found the old stuff was more didicult to mix, and tended to be a bit inconsistant, and never got hard enough to sand well. The West, on the othe hand, is a finishing resin, and does contain the wax that Tach spoke of, but is washed off with plain water before sanding begins. And as long as the wax is removed, additional coats are not a problem. When I get going on the new Chris Craft I'll be glassing that, so will offer details and photos of the process.
PAT
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Old Mar 31, 2004, 09:17 AM
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I look forward to it!

I think there's something out to get us modellers. No sooner do we think we have something taped than along comes a problem that's not only obscure to solve but makes hard work of what we expected to be a straightfoward job.

Oh well, I suppose that's why we persist.

I was talking to a flying pal about getting things done, and he reminded me of the old saying 'A well planned project only takes twice as long as expected. An unplanned one four times as long.'

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Old Mar 31, 2004, 11:04 AM
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PDX, OR
Joined Dec 2002
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How about some of the repair agents suggested here by Jeff Herne?
http://www.finescale.com/fsm/communi...TOPIC_ID=17829

I said bondo, really, I did....
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Old Mar 31, 2004, 02:05 PM
Edina Model Yacht Club
Bloomington MN
Joined Apr 2002
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Tachikaze;
I once had that same problem and it was also with balsa wood. After 3 attempts at re-applying epoxy, I found that I actually had to cut the balsa out and replace it. Frustarting as h***. To this day I do not know what caused it other than it was something in the wood.
George
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Old Apr 01, 2004, 06:39 PM
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United States, OR, Eugene
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I went over the entire surface of the hull with acetone. This had the effect of taking the sticky out of all of the sticky sections.
I have filled one small spot with 5 minute epoxy and one small spot with JB Weld. I will be sanding them this evening.
Details to follow.
It is suspected at this time that the initial material that created the problem was polyester resin that was old and perhaps not well mixed. But at the time it was used on the fireboat hull ( which is flat on the bottom) it was also used on the Shimakaze hull, a rounded warship hull. No defects on the Shimakaze.
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Old Apr 19, 2004, 03:19 PM
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Update on the fiberglass problem.
What I ended up doing on both boats that had this problem ( HIJMS Shimkaze and LAFD Fireboat #2) was to cut out the sections of glass that was soft enough to remove with an xacto blade. I then whipped these sections with acetone to remove the sticky. I filled with JB Weld and then sanded smooth.
The problem there was that with the sanding I would expose sections that were then soft again.
What I believe happened was that the original resin was a polyester resin that had an old and out of date hardener. The superficial surface hardened, but the deeper section did not. As I sanded to remove defects I exposed the bad deeper resin.
What I ended up doing was using paint to fill in the defects on the edges of the JB Weld. I still must have bad deep resin, but I am unwilling to to tear the whole hull apart to fix this. I have now, no exposed areas of bad resin with the pain on. Will it occur if I hit and scratch the hull Possible, but I plan to finish off the painting with a clear coat of enamel or acrylic to try and seal. I think that this will work fine for the fireboat, it might not be as effective on the HIJMS Shimakaze as this boat will recieve combat damage. ( not as much as if it were an allied ship , but damage anyway)
Thank you for the recommendations.
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Old Apr 19, 2004, 04:51 PM
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Tach, Glad to hear the fiberglass problem is, for the most part, behind you. The only thing left to do now, is just don't hit anything!!
PAT
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Old Apr 19, 2004, 04:57 PM
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Not too concerned about hitting anything with the fireboat or the Shimakaze. More concerned with what happens when hit by these allied drivers. They are not too terribly bright or accomplished when it comes to manouvering their ships in combat.
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Old Apr 19, 2004, 05:00 PM
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Collision is iminent

Sound to me like hasardous duty pay is in order
PAT
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Old Apr 19, 2004, 05:02 PM
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Ask Umi what happens when a ship on a direct collision course fails to alter that course. She has a lot of experience with that
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Old Jun 21, 2005, 02:10 PM
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Way back in March of 2004 is when I started this post. I had fiberglassed two boats at one time. The LA Fire Departments boat # 2 and a R/C combat ship the HIJMS Shimakaze. I was more concerned about the appearance of the fireboat as this was to be a scale pretty boat project.
After several months of trying to find a way of getting the resin to harden I finally gave up. I had tried applying new resin over it, reglassing it, cutting out sticky sections and filliing with Evercoat Resin filler, nothing worked. The underlying original coat would come through. I eventually pulled all of the glass off of the fireboat, refinished the sheeting and am now glassing over this.
The Shimakaze did not appear as bad as the fire boat, but now I am seeing the same problem in many sections of the hull. I have also used the resin filler which allows the under lying sections of sticky to bleed through. New coats of resin eventually bleeds through. See the photo.
I am planing on striping it all off and reapplying new glass. When cutting it away I noted that there are areas where I can not cut away easily, it appears attached and dry. What do you think about the idea of trying to save those sections ( which are large) and filling in the cut out areas, or just say screw it and pulll it all off?
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Old Jun 12, 2008, 01:51 PM
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This is an update on this post with regards to what Umi and I eventually figured out was the problem here. And I think that this may be an important issue for some of us who do a lot of different projects.
Thank you for all the input with regards to the fiberglass issue, but what we found out was not that there was a material on the boat or that the catalyst was old, but what should be basic resin use knowledge, DO NOT MIX YOUR RESIN TYPES
Because of years at work on multiple projects, I will often run out to get some materials and use some of it, and not all of it.
The base issue here was the use of a resin, perhaps polyester, followed later, after the resin had set with epoxy resin. You can not place the two over each other.
While building up a springer tug boat hull, I had a deck piece that had a few defects in it. I was building a whole other boat to be used as a prize in our Tualatin Regatta ( August 9th), using polyester resin. The first boat was done in epoxy resin. As a test, I placed some of the polyester resin on the deck of the epoxy resin boat. And low and behold, the exact same issue that I was dealing with in the beginning of this thread.
This may be old hat for some of you ancient guys, but it was a new issue for me. So now, all the polyester resin is going to disappear, not that it is bad or anything, but it smells so much worse than the epoxy resin. I will now remain with the epoxy resin for all my projects.
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