Earlier this week in Hauk's "Another Sawmill" thread I posted some comments on wood joint design and gluing methods, specifically the Ambroid/Acetone Glue Method. I made reference to an article on the subject I published twelve years ago in the Narrow Gauge & Industrial Railway Modelling Review. Prompted by the interest, I have updated the article with new illustrations and information and published it on the Roughboy (http://roughboy.net/) blog. It's a lengthy article, so rather than post it here, I've just included a couple of teaser illustrations. I plan on adding a couple of more dovetail joint photographs from the cabinet-makers' bench I built and will do so once the bench has been returned by our swine former business partner, hopefully within the next 10 days or so if the settlement continues to progress as planned.
(https://www.finescalerr.com/smf/proxy.php?request=http%3A%2F%2Froughboy.net%2Fimgs%2FDadoButtJoint.jpg&hash=8c10f73066fba7c48cffd47c821bd5bb4d60d969)
(https://www.finescalerr.com/smf/proxy.php?request=http%3A%2F%2Froughboy.net%2Fimgs%2FHalfLapJoint.jpg&hash=372a0e899d675ffcf2b5167b38052050706ef385)
Paul
Quote from: Roughboy on November 20, 2009, 09:20:14 PM
Earlier this week in Hauk's "Another Sawmill" thread I posted some comments on wood joint design and gluing methods, specifically the Ambroid/Acetone Glue Method. I made reference to an article on the subject I published twelve years ago in the Narrow Gauge & Industrial Railway Modelling Review. Prompted by the interest, I have updated the article with new illustrations and information and published it on the Roughboy (http://roughboy.net/) blog. It's a lengthy article, so rather than post it here, I've just included a couple of teaser illustrations. I plan on adding a couple of more dovetail joint photographs from the cabinet-makers' bench I built and will do so once the bench has been returned by our swine former business partner, hopefully within the next 10 days or so if the settlement continues to progress as planned.
Thanks for posting the article, much appreciated! A very interesting read.
I definetively are going to try the Ambroid method.
As Ambroid cement is not available locally, I am looking into alternatives.
My first try will be the Humbrol balsa and soft wood cement.
If that fails, I have read that some people make their own glue by dissolving acetate/celluloid in acetone. Could this work?
But where do you find a reliable source of acetate/celluloid in a world that refeeers to any non-wood, non-metal material as "plastic"?
Regards, Håvard H
Thanks Hauk, I'm glad you found it of interest.
I'm not familiar with the Humbrol Balsa Cement, but it's probably worth a try. A few simple experiments with it will tell you whether it will work or not. Certainly be easier than melting a bunch of plastic spoons or film strips in Acetone.... ;)
Other potential sources for Ambroid or perhaps a similar alternative, are outdoor stores or shops that sell canoes. Ambroid was originally developed around 1900 as an adhesive for making field repairs on birch bark and canvas canoes. (It apparently also makes a good fire starter!) Evidently the formula for the glue has remained the same with the exception that they now use recycled cellulose and an amber dye to retain the original amber colour. Traditionalists in the canoe community still use it. Northwoods Canoe Co. (http://www.wooden-canoes.com/index.htm)
Paul
Beautiful diagrams! Wish I could do graphics like that.
For miniature woodworking techniques, I don't think there is any finer reference than Harry Smith's "The Art of Making Furniture in Miniature". He explains very simple techniques for accurately duplicating the common woodworking joints, plus a lot of other extremely useful info and superb eye candy. He works in 1/12 but the ideas can be rescaled to suit. Amazing book.
Dave
Thanks Dave. I'm not familiar with the Harry Smith book... I'm going to have to look that one up. I trained as an apprentice in traditional cabinet-making many years ago with Wendell Castle & Stephen Proctor. I learned to cut all these joints perfectly by hand before we were introduced to such wonders as table saws, band saws, shapers, morticing machines and so on. As I recall we used an excellent book by C.H. Hayward called Woodwork Joints as our primary reference source. Eventually though I had to give up building furniture as I am allergic to sawdust... :( >:( - it aggravates my asthma something fierce. Even now, when I'm cutting scale lumber and working on wood models I have to wear a mask.
Paul
Quote from: Roughboy on November 21, 2009, 08:17:54 AM
I'm not familiar with the Humbrol Balsa Cement, but it's probably worth a try. A few simple experiments with it will tell you whether it will work or not. Certainly be easier than melting a bunch of plastic spoons or film strips in Acetone.... ;)
The Humbrol balsa cement dissolved just fine in Acetone. So it is probably the real McCoy.
But the technique did not work very well for me. I am not sure where the problem lies, because I did a reference glue joint with full strength balsa cement on two pieces of basswood. But I got a far weaker joint than I can get with white glue.
So neither a joint made with Pauls technique or an conventional glue joint worked.
I´m in fact quite puzzled, you should be able to glue basswood with balsa cement, right?
Reards, Håvard H
Quote from: Hauk on November 22, 2009, 11:42:27 AM
But the technique did not work very well for me. I am not sure where the problem lies, because I did a reference glue joint with full strength balsa cement on two pieces of basswood. But I got a far weaker joint than I can get with white glue.
So neither a joint made with Pauls technique or an conventional glue joint worked.
I´m in fact quite puzzled, you should be able to glue basswood with balsa cement, right?
Reards, Håvard H
I have glued basswood with balsa cement before successfully, however it is as has been mentioned before important if gluing on the end grain that you pre-seal the end grain with one thin coat of glue , let this dry and the n apply cement again .. I apply very thin coat to both surfaces .
Would agree that a glue joint like this will never be very strong unless you form some form of joint or add some form of reinforcement like a brass pin, etc.p
Havard:
Since I haven't experimented with Humbrol Balsa cement, I can't offer a specific solution. Balsa cement is not known as being an overly strong product. It could be that diluting it with Acetone weakens it even more. A couple of model airplane enthusiasts I know switched to Ambroid early on because it is a much stronger and more tenacious adhesive than the standard balsa cement. Ambroid is quite strong for a cellulose cement, afterall it was developed and is still used for repairing leaks in canoes, not a task you'd want to trust to a weak adhesive.
The important point to remember is that end-grain joints, regardless of glue type or wood type, are inherently weak because end grain has no glue strength. Any form of butt joint is going to be stronger if it includes some form of mechanical connection.
Paul
Paul
Apart from the glueing aspect, this topic is interesting as it presents various ways to make better joining surfaces on wood (dadoed butt joint, half lap, and others on your blog page). I was wondering if you used specific tools to accurately cut the wood. I suspect if I had to do this, I would mark the places to be cut and use files, but it might not be as precise as required.
Paul
Your article mentioning CA glues decaying over the years made me go check on some plastic models I built back in the early to mid 1980s. After I discovered Zap a Gap CA, I used it for gluing and gap filling nearly everything where I formerly used liquid cement and auto putty.
Only where I used baking soda for additional filler material, or where I used CA to fill grain on wood is there any sign of oxidation or decay. The wood has surface cracking that shows through the paint, the baking soda has a sort of sticky brown residue on it. I recall both those effects started showing up a year or so after application, part of why they ended up unfinished in storage.
I'm glad to report all other models, including an unfinished one with large areas gap filled with CA show no sign of any change. I was able to check the CA glue surface very carefully on that one, still shows the grain from the fine sand paper I used, with no deterioration at all. Models were stored in normal room conditions.
I'm not advocating the stuff or doubting that it can be unstable, but I think stability may differ with the brand and addititives, probably storage conditions too. I would not use baking soda again, or an additive like Zip Kicker. These days I use mostly Elmer's white glue for wood and paper. As you said, there is no substitute for making parts that fit properly!
Dave
Frederic:
I use the Preac][url=http://www.preac.com/table_saw.htm/]Preac (http://[url=http://www.preac.com/table_saw.htm/)[/url] Micro-Precision Table Saw to cut all my wood. I use a range of precision slitting blades, 2" in dia. and various thicknesses: .016", .020", .028", .032", .040" & .052" depending upon the width of cut I need or amount of material to be removed. I generally use a variety of simple stops and fixtures in combination with a miniature table saw "sled" which greatly simplifies the process of cutting joints in scale lumber. I'm building a new sled now for the saw and plan to document that in an upcoming article on the blog (will also post a link here). A sled is simply a sliding top for the table saw.
I also rarely use Basswood as it is a little too soft and coarse-grained for really precise joint work. It also has what we call a high "mulge factor." This is not a scientific term, but rather was, during my apprentice days, the term we used to describe the level of sponginess in wood. Basswood has a high mulge factor, which means it compresses or squishes when machined, which makes it nearly impossible to do absolutely precise work. The woods I prefer are much harder and more dense, Swiss Pear and Boxwood, both of which machine much like brass or aluminum, very clean, very precise as long as you are using sharp blades.
Paul
Dave:
I'm surprised, but pleased to hear that the CA you were using has not deteriorated over time. There are so many different brands and formulations now in CA adhesives, it's entirely possible that one or more manufacturers have addressed the archival issue. It's no surprise that the CA bulked up with baking soda (sodium bicarbonate) has deteriorated. Though a fairly simple chemical in itself, sodium bicarbonate has many and various reactions when mixed with other chemicals, so I expect you essentially have what is colloquially known as a "science project." Generally an alkaline used to reduce acidity, it can, in combination with certain elements, produce an acid. Whatever the chemical outcome, it's not good for making a clean glue joint.
And yes, there is no substitute for making parts that fit properly. A tried and true basic test of craftsmanship is the precision or lack thereof in joint assembly, what my instructors used to refer to as "Gaposis."
Paul
Thanks for the detailed explanations, Paul.
Great info Paul. Thanks!
MR
Nice read Paul.
I finish trim houses.
Gaposis ..good one!
Philip
Thank you for the info Paul, good read. I can't help but add how impressed I am with the holding properties offered by the newer polyurethane glues on wood (Gorilla glue, etc.) If one can get around the expansion issue, they hold remarkably well. This from someone that began their woodworking career mixing the old fish and hide glues.
Thanks for the good words guys, I'm glad you found it of interest.
Chester, the glues such as Gorilla Glue are quite strong, though I'm not convinced they have their place in a craftsman or model shop. The expansion issue is a drawback but they do seem useful for coarse repair work. In the long run though, it's usually much easier, quicker and more effective to make a clean joint & glue with PVA - much quicker clean up after the joint cures for one thing.
Phil, doing trim work I'm sure you've had to replace many example of gaposis... glad you like the term. We had a few "technical" terms we used such as "mulge factor" that I referred to in a post below and "California Roundover." The last applied to a prevalent trend in the 80s & 90s in furniture design and cabinet work from the west coast where it seemed that whatever or wherever the edge was, it was rounded over! We labeled it California Roundover which was not intended as a complimentary description. :)
Paul
Paul,
You forgot to use the term "Shmooie" (Caulking)...as in the prevalent use of "1/2" Shmooie" to fill moulding joints and spaces in so much of the new construction these days. ;) ;D
MR
That's a good one Marc, haven't heard that before. So are you saying that 1/2" is the current tolerance standard in construction these days ;), as in "Just cut it within 1/2" and be quick about it. We've got six more of these to frame this week." Evidently 90 degrees is also no longer considered a right angle. ;) ;D
We did use "scooch" though, as a term for precise adjustments in accurate positioning of stock before cutting or assembly ;) ;D, as in "just move that over a scooch so the blade lines up with the cut line." That one however, was not unique to our shop and I believe has come in to fairly common use.
Paul
scooch- hey take a scooch off this ;D
When I first started in the business 1998 (after the army put me out to pasture) as a nailer we were doing these spec houses for this crappy company. The trim was always short or long and the saw guy would look disgusted when I'd take a stick back and tell him it wasn't right. They (job super) (saw guy) could care less about fit and we all got to the point of where we would just "nail it" "let the painter get it". Like Marc mentioned 1/2" gaps, out side corners all screwey. I was just thinking OMG I'd wouldn't buy one of these crap houses or have them build a dog house. We'd run thru 3 a day.
Sadly, there was more money in production trim than finish trim. Difference..... screws verses rail bolts.
pinning verses splines.
California roundover. he he, cheap and quick
Philip
Quote from: Philip Smith on November 27, 2009, 09:51:27 AM
California roundover. he he, cheap and quick
Philip
Yep, that was the point, apart from the wholly indecisive design solution aspect. These sort of vernacular terms are always entertaining.... ;)
Paul
Quote from: Roughboy on November 30, 2009, 06:55:06 PM
Yep, that was the point, apart from the wholly indecisive design solution aspect. These sort of vernacular terms are always entertaining.... ;)
Paul
Entertaining yes as long as you aren't the one responsible for the finished product. I have had such things as "This ain't no church" and " you can't see it from my house" thrown at me from time to time when wanting to see a better fit and finish. Not the kind of response a contractor wants to hear from his men. The best retort I can come up with is "I'll pay you what I think it's worth then".
By the way, the most common term for those discretionary cuts from the younger bunch is nano, as in "take a nano off" And we refer to caulking as spoodgie like "spoodgie that hole" or "put some spoodgie in it"
Back when I started, it was always a pleasure to listen to the old timers as they were always metaphorical. Things were "sharp as a sailor's tongue", "dull as a hoe", "straight as a gutted toad" and "bowed like a fat woman's ass" to name a few. My favorite when viewing a poorly done job was "looks like a dog's breakfast"
Chester:
A dog's breakfast is a tried and true classic... have been using that one for years in all manner of situations when confronted with a particularly appalling piece of work. "Bowed like a fat woman's ass" is a new one on me... I'm going to have to remember that one.
Paul
Dave & Paul- I read a bit of CA adhesive science in a research article summary on line. Apparently it is used to cover dinosaur bone fossils but the method was never really proven. The researchers found that acidic bones inhibited CA degradation while alkaline bones accelerated the problem. Hence the baking soda joints on the models mentioned going bad first. Also, butyl based CA lasts the longest. But the summary offered no time frame.
Also RC model airplane folks use AC quite a bit on wood joints but I guess their creations aren't expected to last 100 years for some reason...
Welcome to the forum John. I'm curious about the CA use with dinosaur bones. Were they using it as a sealant or do you know the reason for covering the bones with it? It does seem to have many and varied uses. The CSI forensic folks use it's gaseous qualities to reveal latent fingerprints from surfaces that are otherwise unreadable.
Paul
It was a brief summary but it seems they use it for protection and to hold the chips on. It must allow them to store them but keep them available for investigation, unlike the old way of the plaster cast.
Thanks Paul, I always admired the clean presentation of Russ's publications and certainly enjoyed looking at the modeling. So I thought I occasionally could add some wit or wisdom to the group.
John:
Looking forward to your contributions to the forum. Russ is known for being uncompromising in the work he does with his publications, but we try not to tell him that too much, because he just gets to be so difficult to deal with... ;)
It's interesting that the archeologists and archivists are using CA in this manner. It's a basic principle of archivists to not do anything to an artifact that can't be undone without risking the integrity of the artifact. The CA application seems to me like a risky maneuver but I would expect that they've completed some fairly complex chemical studies... one would hope at any rate.
Paul
John,
welcome. but with this:
QuoteSo I thought I occasionally could add some wit or wisdom to the group.
your in the wrong place. ;D ;D
Jacq