Colored glue and bleeding

[Bats]

I've got a recurring problem, and didn't know if anyone here might have a creative (or "how the hell did you miss something so obvious?") solution for it.

I'd like to be able to use pigmented epoxy in wood blanks - whether it's for assembling brick-y segments like this one:

(which in retrospect looks like it may not have needed it, but I wasn't confident that my cheap bandsaw was making the perfectly flush cuts required, and I didn't want to expose gaps full of clear epoxy around the black veneer)

...or Jim Boyd-style spider pens like this, which relies on a pigmented epoxy "inlay":

The problem, as the pictures illustrate, is that the color tends to bleed into the grain of the wood in a most unsightly manner. I finally broke down and started stabilizing the holly/maple for the spider pens in advance (which works, although it's no fun to scroll saw), but stabilizing a handful of blanks is a little different from stabilizing a stack of sheet stock, so I was wondering if maybe there was some workaround I'd overlooked when segmenting. Well, aside from "throw it out if the cuts weren't perfect", which is my alternative go-to.



-Bats

 

[sorcerertd]

Can't say I have experience with it, but my first thought is maybe seal the wood with a little thin CA first?

 

[MRDucks2]

I was gonna say exactly what Todd said but he said it first so I won't say it because I don't think you need me to say what he already said for you to see it.

 

[Bats]

Can't say I have experience with it, but my first thought is maybe seal the wood with a little thin CA first?

The same thing occurred to me when I was staring at this most recent failure (the segmented one - I haven't made any spiders in a couple years now), but I wasn't sure if it would risk makeing the fit worse. CA and then sanding it back is another possibility, but that, of course, could cause its own unevenness.

 

[Bats]

I was gonna say exactly what Todd said but he said it first so I won't say it because I don't think you need me to say what he already said for you to see it.

*blink* *blink*

See what? I see nothing!

 

[jttheclockman]

Yes sealing the woods with CA should work well. In the first segmented blank there should be no need to use colored epoxy. I would use a clear Light woods can become contaminated as you see.

 

[flairwoodworks]

What about using an epoxy coloured with a pigment instead of a liquid tint? Or perhaps a more viscous epoxy?

 

[Bats]

What about using an epoxy coloured with a pigment instead of a liquid tint? Or perhaps a more viscous epoxy?

I've tried both alumilite liquid dye and iron oxide pigment without seeing much difference. When I was working on the spider pens I even experimented with things like mica pigments, powdered jet, and (dry) aniline dyes.

A more viscous epoxy something I hadn't considered - although I'd somehow gotten the vague impression that viscosity tended to track inversely with cure time (I know my 5min is thicker than my 30min, which is thicker than my 1.5-2hr WEST System), and I know the slower cures are considered to create stronger bonds (I'd be reluctant to use 5min for segments). It would also be problematic for detailed inlays like the spider, since the epoxy has to be thin enough and slow-curing enough to flow into narrow spaces and for bubbles to be vibrated out.

I'll admit, though, I don't really know my epoxies very well. If you've got a high-viscosity, slow-cure clear epoxy in mind that's available in small quantities (wow, that's getting pretty specific... should I say it has to be affordable, too? and come in biodegradable packaging? with a pink glittery logo in the shape of a dancing axolotl wearing a tuxedo with a bowtie and a shirt with exactly six buttons?) then I may give it a shot.

 

[flairwoodworks]

I did epoxy inlay in maple once, tinted with a universal tinting colour (liquid) and had no issues with bleeding. For the bleeding to occur, the colour - not just the epoxy - would have to penetrate the wood. In this case, it looks to be the end grain. I'm surprised to hear that some of the solid colouring agents caused issues as well. What about fine sawdust from sanding mixed in with epoxy?

Another option you could try is first filling the voids with sawdust or other solid (as opposed to liquid) colouring agent, then applying CA glue to saturate it and create the bond.

 

[Bats]

I did epoxy inlay in maple once, tinted with a universal tinting colour (liquid) and had no issues with bleeding. For the bleeding to occur, the colour - not just the epoxy - would have to penetrate the wood. In this case, it looks to be the end grain. I'm surprised to hear that some of the solid colouring agents caused issues as well.

I've had very uneven results with maple. Sometimes it doesn't bleed at all. Other times - like that segmented blank (which is maple, cherry, and walnut) - it bleeds like crazy. To be fair, though, the maple I used this time around was lousy - very loose-grained, fibrous, and, for lack of a better word, fuzzy. It didn't finish particularly well either. It was some leftover 1/4" stock that I'd picked up for CNC work, that turned out to be too cupped to be useful (apparently the entire batch was bad - they refunded the whole order, leaving me to figure out some way to make use of it).

And yes, not surprisingly it's always the end grain it bleeds through (although with inlays that "end" grain may be smack in the middle).

What about fine sawdust from sanding mixed in with epoxy?

That's a thought - although it takes an awful lot of work to get that much sawdust (the closest thing in the shop to a power sander is this thing they tell me is called a "lathe"). It might be viable for the segmenting work, but probably not large inlays (the spider design is cut straight through a 3/4" blank, so there's a fair bit to fill).

I'm also a little worried that loading the epoxy that heavily with a filler might change the properties/bonding strength, though. The powdered pigments give a solid color with a tiny quantity, but I suspect doing the same with sawdust will require at least a 50/50 mix. The viscosity would obviously be dramatically increased, too - so it might work for segmenting (although JT's right - in this particular case it probably wasn't necessary), but that's another strike against it for inlays.

Another option you could try is first filling the voids with sawdust or other solid (as opposed to liquid) colouring agent, then applying CA glue to saturate it and create the bond.

My favorite method of void-filling (and one I have yet to notice bleeding - although it's usually only on small patches)! I've seen it done with coffee grounds, too - and I used the same iron oxide pigment to fill bubbles in the black epoxy on the spiders. I'm not sure if it's really applicable to either the segmenting or inlay use cases, though.


One other note... I feel like I keep shooting down ideas here, so I just wanted to say that it's not because I'm ungrateful - I really do appreciate all the suggestions, and I'll probably be trying a few... just as soon as I recover from the (multiple) frustrations on the last attempt.

 

[sorcerertd]

This is a stretch for the segmenting, but for inlays like the spider, have you considered packing it with poly clay? The baking process is very short, so it shouldn't really harm the wood (well, probably not most of them). If nothing else, it might give you ideas for different projects?

 

[Bats]

This is a stretch for the segmenting, but for inlays like the spider, have you considered packing it with poly clay? The baking process is very short, so it shouldn't really harm the wood (well, probably not most of them). If nothing else, it might give you ideas for different projects?

The heat probably wouldn't be a big deal - Cactus Juice gets baked to cure it too. Granted that's usually around 200°F, and it looks like poly clay is closer to 300°F, but I know I've run maple blanks with some aging and stubborn juice up even higher (it's supposed to be stable to at least 400°F, if I remember right) and left it for hours on end. The bigger problem (and I could be way off base on this - calling my experience with poly clay "limited" is an insult to people with limited experience) is forcing it into the details:

The spider's legs are cut with the finest scroll saw blade I could find - probably not much more than .025" thick, by the full thickness of a blank (the drawback to stabilized blanks here is they're tough to cut - and tougher still to cut without unsightly burning of the resin). Usually I have to use a fairly low viscosity epoxy with a vibrating table (read: clamp the sucker to the scroll saw & let 'er rip), and even then I end up with areas it didn't reach. Is there any way to thin poly clay way down? Or I wonder how it would react if I stuck it in a pressure pot and cranked it up to 120psi?

Even if it doesn't work with the spider, though, it's definitely an interesting idea. I don't recall ever seeing anyone making wood/poly clay hybrids... does it shrink or pull away from other materials when it cures?

 

[jttheclockman]

Just out of curiosity did you see the article in the library about making those pens?? I believe you are creating something that is easily fixed and may require you do do some testing and that is it. I will tell you I have used epoxy glues and tinted with epoxy tints which are rather thick. Never use tints like dyes such as transtint or wood dyes. I have tinted 5 min epoxy as well as system3 t88 24 hour epoxy and never had any bleed through because it is thick.

file:///C:/Documents%20and%20Settings/Administrator/My%20Documents/Downloads/segpenblanks.pdf

Could not get this link to work but if you go to Library resource and click on the Segmenting catagory and scroll down to the spider segmented pen blank you will see the same thing you are making.

 

[sorcerertd]

Now that I see how you cut the spider shape, poly definitely won't work. Oh well, was just a random thought. Once it's turned, thought you might be able to push it in using a rolling pin type action.

 

[flairwoodworks]

One other note... I feel like I keep shooting down ideas here, so I just wanted to say that it's not because I'm ungrateful - I really do appreciate all the suggestions, and I'll probably be trying a few... just as soon as I recover from the (multiple) frustrations on the last attempt.

No problem here. The wonderful thing about people is that everybody has a different set of experiences, knowledge, and ideas and all I hope to do is present something different. It's up to you to figure out what works for you!

 

[Bats]

Just out of curiosity did you see the article in the library about making those pens??

Yep - that's where I originally started from, although I eventually ended up using an entirely different method for the webbing (Boyd's method is definitely more straightforward - and probably easier, at least if you have a tablesaw - but struck me as terribly wasteful (and/or I was terribly poor and short on wood) and doesn't keep the grain alignment (which, granted, became pretty much irrelevant when I switched from maple to holly)).

I believe you are creating something that is easily fixed and may require you do do some testing and that is it.

Possibly - although I did a lot of testing at the time, and the only thing that seemed to offer 100% protection against bleeding was stabilization (which I ended up sticking with, despite the abovementioned troubles with the scroll saw).

I will tell you I have used epoxy glues and tinted with epoxy tints which are rather thick. Never use tints like dyes such as transtint or wood dyes. I have tinted 5 min epoxy as well as system3 t88 24 hour epoxy and never had any bleed through because it is thick.

Any thoughts on getting a thick epoxy to flow into fine details? Heat works, but only because it lowers the viscosity, which brings us back to the same issue. Pressure works, but encourages penetration - again, same problem.

To be clear, while I can't find a specific number (the MSDS lists 10-12k cps for all of their varieties), the BSI 30min I usually use isn't a super-low viscosity - nothing like the thin WEST System coating epoxies - just thinner than most 5min epoxies I've worked with.

I think we (or, let's be honest, *I*) might be getting a little hung up on the specific use case, though. While I hope to make a few more come Halloween, the spider pens aren't something I'm currently working on (and I've managed work around the issue by stabilizing the wood first, even if that creates its own headaches) - they were just a good example (and one I had a plenty of pictures of) of one of the situations where I've regularly run into trouble with bleeding pigments. What I was really hoping to get at was whether this sort of bleeding (in various circumstances) was something other people had dealt with, and if generally applicable (or frequently applicable - the only thing that works in 100% of cases is an over-broad generalization) solutions had been found. Sealing flat pieces with CA is a great idea I'm looking forward to trying out, but of limited use for inlays. Stabilization works, but causes difficulties in cutting. Using only very dense-grained woods is probably another option, but also limiting (not that I'm likely to be trying inlays in poplar, pine, or balsa).

file:///C:/Documents%20and%20Settings/Administrator/My%20Documents/Downloads/segpenblanks.pdf

That "file:///" at the beginning means the link is to a file your local hard drive - in this case it's where your browser downloaded the PDF before opening it to view. Something about the way a lot of library PDFs are accessed makes them confusing/frustrating to link properly. I recently discovered I had a whole folder of broken bookmarks that I'd thought were pointing at library docs)

For anyone else following along at home, this is the source of the spider: http://content.penturners.org/library/pen_blanks/segpenblanks.pdf

 

[MRDucks2]

I saw you make several references to concerns over affecting the strength of the bond of the epoxy with modifications. Just curious, but are you possibly overthinking it a little? How much bond strength do you believe you need relative to the wood used and final thickness?

 

[Bats]

I saw you make several references to concerns over affecting the strength of the bond of the epoxy with modifications. Just curious, but are you possibly overthinking it a little? How much bond strength do you believe you need relative to the wood used and final thickness?

I'm probably overthinking it (I'm really very good at that), but if people consider the difference in strength between a 5min, a 30min, and a 24hr epoxy to be significant, it seemed relevant - and I know I've had trouble in the past when I've overloaded wood glue with sawdust (although the details of that project escape me now).

 

[MRDucks2]

I'm probably overthinking it (I'm really very good at that), but if people consider the difference in strength between a 5min, a 30min, and a 24hr epoxy to be significant, it seemed relevant - and I know I've had trouble in the past when I've overloaded wood glue with sawdust (although the details of that project escape me now).

If you overload any glue (or other liquid for that matter) with enough of a suspended particle you will lose the ability of the glue to adhere to anything (or the liquid to be liquid). You simply have used all the adhesive on all the surface area of the particles and made a dry or nearly dry paste. Wouldn't matter if it was a 1 ton epoxy or a 30 ton epoxy.

Most of the positions here on epoxy adhesive (not all) involve working time under the conditions the work is performed. Some involve the ability of the adhesive to adhere to certain material or how it reacts.

Once you exceed the strength of the base material (wood) the strength of the adhesive becomes rather irrelevant (when everything is properly mixed, applied and cured).

So, your thinking is mostly correct but it is more a ratio of additive than it is epoxy strength issue. There are two part epoxies that are solids that you knead together.

 

[jttheclockman]

Epoxy will not flow on its own. For what you are doing easy to use a spatula and push into crevices. You will see if it is full on underside. You are over thinking this and I am out of this because you are knocking every suggestion down anyway. I am a pretty good scrollsawer and have done infills with epoxy in oak and have to tell you this is one of the most open grain wood around. So to cure you problem stick with stabilizing and change scrollsaw blades. If you have to use a metal blade than do that. I scrollsaw ipe. Use quality scrollsaw blades and not junk from Home Depot. That is all I can say. Good luck.