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Facets, the Next Logical Step #7: Gluing Up the Dodecahedron

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Blog entry by shipwright posted 1289 days ago 2407 reads 6 times favorited 14 comments Add to Favorites Watch
« Part 6: Dying the Veneer...... (Again??) Part 7 of Facets, the Next Logical Step series Part 8: Hinge Assembly and a Little Detail. »

The original segment here asked “How hard can it be to make a dodecahedron? Well the answer seems to be pretty easy….. but there are lots of ways to make it harder. When I first assembled the MDF pieces off the saw I thought that the fitting part was going to be the easy bit and that the dying and marquetry would be the sticky parts. That remained my belief until the final assembly time arrived and I realized that with the allowable tolerances it was going to be an interesting fitting job after all. It turns out that all the little operations associated with veneering, trimming, wetting, drying, warping and unwarping had each taken a small toll on the initial accuracy. The sum of these little discrepancies was enough to require a certain amount of “fitting”.

This is the setup I used to “fine tune” the fits. It wasn’t the angles that were out as much as the dimensions. Nothing was out much but any small mismatch in length on adjacent pieces would show as a gap in one of the joints, so the fine tuning began. The sanding disc now stays put and the jig slides the piece across it. It allowed me to take off very small amounts and by applying more pressure to one or the other end, I could take a little more off one end if I wished.

This photo shows the two critical areas that had to match perfectly for length, the joints between the sides and the bottom and the joints between sides. Herte they’re getting pretty close to good.

At last it’s time to summon up some courage and glue up the bottom. The bottom was done first for the obvious reason, to practice before gluing up the top. The pieces have been assembled outside up, taped to exactly match at the corners, turned over and glue has been applied to the mating faces. The stick was a piece of scrap I had that approximated the open angle well enough to make a good glue spreader. In the background you can see the clamping system parts I came up with.

And here are the parts in the photo above in service clamping the sides of the bottom together. The pieces of cloroplast have vee notches cut in them that hook on the pentagons’ tops to keep the wedges from slipping down under pressure. It worked really well.

The fact that all the angles are the same should guarantee a symetrical glue up but I didn’t trust what could easily be uneven pressure exerted by the bungee cord so just to be sure, I made a fitted pentagon to check the inside. It actually did need a little persuasion but once it was right it stayed that way nicely. The corners of the pentagon were removed to avoid getting it stuck in there.

When the sides were glued up I did a last fine tuning of the bottom and glued it in with masking tape. After a quick sand up to remove unwanted glue this was the resulting bottom all glued up. I must have gone through half a roll of packing tape assembling, disassembling, tuning and reassembling and then repeating. Between the top and the bottom I’ll bet I pre-assembled these things twenty times or more before finally gluing them.

Here’s the top glued up. For reasons that would take too long to explain I couldn’t use the same tape up / glue up sequence with it and as a result the top was glued up with the sides all at once. This was of course the scary one because of the marquetry.

With most of the panic over and the glue ups successful this is pretty much where it stands today. This part has taken a lot more time than I expected but I’ve learned lots of interesting things about the various processes involved.

Thanks for dropping in. I hope you’re still enjoying this as much as I am.
As always comments, critiques and questions will all be acceped and appreciated.

Thanks again

Paul

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/



14 comments so far

View GaryL's profile

GaryL

1074 posts in 1427 days


#1 posted 1289 days ago

It looks like your seeing the light at the end of the tunnel.
It must be a relief to get it glued up after the various challenges you’ve encountered.
Keep up the unbelievable work!

-- Gary; Marysville, MI...Involve your children in your projects as much as possible, the return is priceless.

View Bearpie's profile

Bearpie

2584 posts in 1614 days


#2 posted 1289 days ago

This is a super nice project although a toughie unless you know what you are doing and it is very obvious that you are very proficient. I have greatly enjoyed your projects and blogs and find them very informative and interesting.

Erwin, Jacksonville, FL

-- Erwin, Jacksonville, FL

View Gene Howe's profile

Gene Howe

5375 posts in 2025 days


#3 posted 1289 days ago

Amazing work!
Unbelievable patience.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View Schwieb's profile

Schwieb

1476 posts in 2057 days


#4 posted 1289 days ago

Paul,
Noteable and extremely challenging work. You’ve probably spent more time thinking about how to do it, than actually doing. I appreciate and enjoy your posts very much.

-- Dr. Ken, Florida - Durch harte arbeit werden Träume wahr.

View SPalm's profile

SPalm

4740 posts in 2478 days


#5 posted 1289 days ago

Very good Paul.
Boy, a lot could have gone wrong. You seemed to have covered it well. Hats off.

I didn’t catch it until now, but I know you have; You have a five sided figure nestled into a three sided holder. Hmmm. Just thinking. (Actually I don’t know what I am thinking) Interesting problem.

Thanks for showing the glue-up. Glad I was not there.
Steve

-- -- I'm no rocket surgeon

View sras's profile

sras

3777 posts in 1725 days


#6 posted 1289 days ago

Wow – that is a lot of careful fitting! The end result is going to have a magical feel to it. A very fun and interesting story. Thanks for letting us watch!

-- Steve - Impatience is Expensive

View shipwright's profile

shipwright

4833 posts in 1394 days


#7 posted 1288 days ago

Thanks to all. It really is good to be past this part but I’m not all the way out of the woods yet. The current thing is that the top and bottom are not as perfect a fit as I’d like…..bu I’m working on it. I is a little like herding cats.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/

View stefang's profile

stefang

12537 posts in 1930 days


#8 posted 1288 days ago

A wonderful result so far Paul. It’s very educational to read your thoughts and concerns on the various parts of the work. It’s obvious that you aren’t satisfied with anything but perfect, or as near to perfect as it is possible to get. At the same time you let us know that the result didn’t just fall into place without considerable effort. That sets a good example for others.

-- Mike, an American living in Norway.

View shipwright's profile

shipwright

4833 posts in 1394 days


#9 posted 1288 days ago

Thanks Mike

“Perfect” is a term I use as an aiming point, knowing it can not be achieved. I am a strong believer in the much maligned “good enough”. If I wasn’t I would never finish anything. “Good enough” is of course relative to many things.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/

View BritBoxmaker's profile

BritBoxmaker

4336 posts in 1632 days


#10 posted 1288 days ago

Very entertaining, Paul. Skilled and courageous. Particularly like the use of the rope in the glue-up. Grain following looks perfect.

-- Martyn -- Boxologist, Pattern Juggler and Candyman of the visually challenging. http://www.theartofboxes.com

View sedcokid's profile

sedcokid

2663 posts in 2195 days


#11 posted 1288 days ago

You are one talented gentleman! It has be fun watching your blog…

Thanks for Sharing!

-- Chuck Emery, Michigan,

View bigike's profile

bigike

4031 posts in 1884 days


#12 posted 1288 days ago

great work, very tight angles.

-- Ike, Big Daddies Woodshop, http://www.icombadaniels@yahoo.com

View Napaman's profile

Napaman

5315 posts in 2673 days


#13 posted 1283 days ago

i’ve fallen behind on keeping up now that I am back in school but this is looking really cool…love your work!

-- Matt--Proud LJ since 2007

View tdv's profile

tdv

1114 posts in 1666 days


#14 posted 1279 days ago

Only a boat builder would come up with a clamping system like that & a neat sanding jig. I think you prove there’s a solution to every obstacle
Thanks Paul

-- God created wood that we may create. Trevor East Yorkshire UK

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