Project xs750 lowrider

And now for my next trick - a word about fiberglass materials and absorbency.

If you attempt to fiberglass something by wetting a surface and then getting glass materials stuck into it and then try to get the material "wet out" well and all air entrapment removed, you'll find that's not a simple task, especially in tight bend areas. And you'll often see on TV, guys use a foil pan with resin and soak fiberglass cloth and then apply it to the work. You can't do this with mat as easily. So here's what's at issue:

All fiberglass materials are produced using "sizing" - a synthetic material like starch. In fact, way back in the late 50s when I was a toddler, my Dad fiberglassed our sundeck and at that time, the material was actually formed with cornstarch. So imagine you want to wet out glass with resin which is much thicker than water or paint. The first thing that has to happen is that the sizing must dissolve. When you put a piece of material into resin, even in a foil pan, it takes a few moments for the material to become translucent, indicating all air removed and it's saturated. If a piece of material is added to a mold surface, even if the surface is already wet, it takes a bit of work dabbing with the tip of a stiff brush or using rollers to caress the material into the resin. The thing to avoid is too much resin and yet that's the beginner's solution to air in the material or material that won't lay flat - hammer it with more resin. Ideally, you should have at least 60% glass to resin, even with epoxy resing.

Lastly, you can do a very cheap effective "vacuum bagging" of your work using a shop vac and some special materials you can get from fiberglass supply shops. Basically, you lay a non-stick sheet over the wet part of the work, then a layer or absorbent material (an old blanket works), and you can also put some foam scraps or bubble wrap on top to ensure an even distribution of the vacuum loading. Provided you have no sharp edges, you can use ordinary poly sheet for the external bag. I've used a simple shop vac (you must use a shop vacuum because the motor is independently cooled, not by airflow through the suction, because obviously, you're not going to have much flow. I use adapters to a small hose, then an ordinary ball valve with a short piece of PVC on the end - that PVC is cross drilled so it's not easily plugged up and that is inserted above the absorbent area with another layer of absorbent on top. Turn on the vacuum and you'll have effectively 3 - 4 pounds PER SQ IN pressure on your work. This helps a lot to force materials into complex shapes and remove air entrapment. You can Google vacuum bagging and even more advanced resin infusion (where the vacuum setup is enhanced with ports on the mold connect to your resin pot, so the vacuum pulls the resin through the work - and yes that takes planning!)

So there yah go, a bit more blah blah about glassing :D
 
Well said on all accounts Mr. d9canada. Thanks for taking so much time to add so much valuable info. I'd like to add or reinforce the absolutely correct comments on the toxic characteristics of epoxy resins. Certainly they are in general much more benign than in the past, but reasonable care is important for protecting ones health. That said, many other activities undertaken in building bikes, cars, airplanes, boats, etc, etc provide similar caliber risks and in general it is reasonably easy to minimize them. In my opinion the risks should not be off-putting to a sensible person using common sense and having a sense of self preservation, though opinions vary! After all, motorcycles rate pretty high on many folks foolishness scale and all of us here ignore them! I'd like to add, that epoxies, despite your observations on handling, are easy enough to use with a bit of experience just like polyester resin - a bit different perhaps, but I'd say one is no more difficult than the other. Like most things, it takes a bit of exposure to get familiar enough for it to become easy. On that note, I'll offer 2 comments. First, chopped strand mat, unlike woven cloth (as far as I know) is made with a binder (not sure if this is this "sizing" you mentioned) that holds the strands together. Polyester resin dissolves this binder so the mat conforms very nicely to complex and tight shapes. Epoxy does not dissolve this binder, so I can see REALLY not liking epoxy if you had polyester experience first! The binder does no harm in layups using epoxy aside from staying stiff and springy - exactly like it isn't after the binder dissolves in the polyester! Never seen anyone use flour or sawdust etc to thicken epoxy - yikes! My second comment is a technique for minimizing excess resin on difficult shapes and works for polyester or epoxy - though more needed I suppose when using epoxy. I will sometimes paint a very thin coat of resin on my part (or mold) and let it start to cure, having the upcoming layer of cloth completely prepared in advance. When it is very sticky, I squeegee the new layer in place - it is easy to get an absolutely perfect layup this way. Once I am sure it will stay put, I wet out the layer. I use very light weight laminations so this is never a problem for me, possibly heavy cloth or mat is an issue. Very accurate constructions with very low resin content are practical using this technique. And, while this does make for essentially 2 iterations of resin per lamination, I have never observed any integrity issues within laminations. I am , however careful to wet out completely before the "sticky" cures completely.
 
Thanks to everyone for the ideas... I am going to go with a mold of the finished plug. I'll be asking for advice as I go.
 
No better way to rid yourself of the skeletons of a bad fiberglass tank fail, than to gather a mob, some lighted pitchforks and go pillage the local mad scientist's place. I couldn't find a mob and wait...I am the local mad scientist. Get out them marshmallows... the tank is burning.!
 

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Well after a long day of pillaging with a burning pitchfork... I turned on the lights and decided the best way to get the bad taste of the fiberglass fail out of my mouth would be to build TANK II. I got it to its roughed up shape a lot faster this time because I cut the tank in half at the backbone and used a cardboard template of the backbone to draw a mirror image of the backbone on the inside of each half of the tank with a sharpie. Much faster than the way I did it before. Cut my time by 75 %. Today... I'll make the final shape.
 

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TANK II... Much faster than the first time. Split the tank and drew the tunnel on the halves using a template of the backbone. Learning.
 

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Looks great, even upside down! ;D ;D

Markie, if you're using a Windows computer and have your pictures loaded there, you can go into File Explorer, right click on the file and you'll get options including "Open With" click that and you get a choice of several products to use to view your picture.

Right now, I don't now what product your machine defaults to, but I'd strongly suggest you use Windows Photo Viewer, but don't choose that even if you see it on the list. If you have an option below saying Choose Another App, click that instead - you'll see why in a second.

Another window opens up and Windows Photo Viewer should be displayed but now, down below you have a check box lower down with words beside saying something like "Always use this application". So choose Windows Photo Viewer, check the checkbox and then click OK. Now whenever you double click on a picture file in File Explorer, by default it will be opened using Windows Photo Viewer.

So, open a picture and at the bottom you will see tools along the bottom. From far right, the red X closes the application. Next, important to you, are arrows in circles. These allow you to rotate your image right or left. Note that if you rotate an image and then just close the application, you file will be saved in the new orientation.

Next, in the middle are tools that allow you to cycle through other picture files in the same folder where the first file you opened came from. The center tool allows you to have slideshow of all pictures in the current folder. Further left is a button, press that and the picture displays actual size and on the left is a magnifying glass. Click on that and you get a slide control. Slide the slider to zoom in or out. So now you can control your images better, if you're using a computer.

If you're using a phone, let me know what brand and I'll try to help you out on that. I've spent a career doing systems for the RCMP, hence my tendancy to write verbose instruction files :eek: :p ;D
 
I know... every day, I have to go inside, download the pictures from here.save and edit them, then reload them. I do it every day. It's a new galaxy phone and so far, EVERY picture has loaded upside down. It doesn't matter what way I hold the phone either. Always upside down until I go in and edit them.
 
:BTW... I am going the long route and making female fiberglass molds. A little more work, but in the long run... I think it would be better to have the molds if I need them in the future .
 
d9Canada...

I just did a test patch with bondo on the foam carved tank. After it started to dry, hundreds of 3/8 inch bubbles formed on the surface of the body filler. Normal? Should I wait and just sand them down? Never put body filler on foam before... actually... before this, I never did anything with foam. Advice?

Markie
 
Forging ahead... started putting Bondo on the plug today. Immediately bubbles began to form on the tank. I waited a while after the test area... still a little skittish after Tuesday's tank fiasco. But the only way to make progress is to soldier on. So... fingers crossed for a good day tomorrow. A lot of sanding. Good day!!
 

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That pink extruded foam is melted by anything with solvents in it. Bondo will melt it a bit, hence the bubbles. Ideally the foam is sealed before hand to prevent the bondo and paint from melting it. Since you are just needing a plug you might be able to forge ahead, but where there are bubbles there are cavities underneath. The green "florists foam" is the way to go. it is not as readily effected by solvents.
 
... or seal the styrofoam with a couple of coats of epoxy first. Then you can use polyester fillers for final profiling. Doesn't have to be a great bond - you only want the master's profile to last long enough to make your mould.
... and you're going to use mould release wax (4 to 6 applications) and then PVA on the master before making your mould, right?
I had some CNC'ed prototype tooling machined out of white styrofoam in error by a supplier, sealed them with epoxy, used wax and PVA and worked well enough for a couple of parts.
DTT should start a composites thread - a lot of good info from everyone on the above posts.
Pat
 
I should have thought of this before, sorry, but you could use "Spackle" (sp?) the drywall patching material instead of bondo, build it up, sand it. It won't attack the styrofoam and you can get a great finish on it. Then you can paint that. It's way cheaper than using epoxy and I wouldn't bet on that pink stuff accepting epoxy. With the work we've done with epoxy and foam, we found the blue stuff worked OK but I think the white stuff melted. That was years back, sorry at the time I didn't keep notes on that. Sorry Markie, I should have at least suggested that you do a test patch.
 
Darn! I should have thought this might happen. Another thing you could do in future, and again, do a test piece first, but I think you could just paint the raw styrofoam with cheap latex paint and let that set up, then you could use Spackle or even Bondo. The latex should seal the styrofoam enough to prevent the bondo chemistry from intruding, but a test would tell you for sure.
 
Good old Elmers white glue slightly watered down will seal foam to prevent solvent damage, Modge Podge will as well. I use that for making cosplay props, a couple coats then you can spray paint the foam without it eating into it.
 
This time however I would sand the bondo, then use drywall mud to fill the small pin holes that will show up then you can sand and paint and likely be fine.
 
I remember making a class project out of Styrofoam. It was a pretty complex model of a steam engine, and the "main body" was Styrofoam with bits hot glued to it. I was done, less the paint. One coat of black spray paint, and I got an un wanted lesson in chemistry....
 
All is well guys.... I forged ahead with the bondo and even though bubbles appeared on the test area, it was pretty much held in check when I put it on a little thicker. Since I am using bondo to build up and round out the sides anyway, the bubbles were small enough that they sanded out on the first coat and were non-existent on the second coat. Any recommendations on an epoxy product to cover the plug after the bondo is done? "Plugging" away... LOL!
 

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