Attaching Dry Pieces To Each Other

[Stone Spiral]

Hey there,

A lady who uses my studio made a mug and handle, but did not attach them together. She didn't return before they both dried out.

She moistened them both, scored and slipped them, and adhered them together -  but then of course as they dried they began to form cracks along the join.

She's wondering if there is anything that can be done here?

I don't feel confident that there is - I have always added my handles while all clay is fresh or leather hard. I do have some bisque fix I could offer her to patch the little cracks around the handles... might that work?

Any advice would be great - I will pass it on to her when she comes in next.

Thanks!
 

[dhPotter]

Spooze

 

1/3 dried clay, the clay used to make the mug and handle

1/3 Karo syrup, or any cheap syrup

1/3 white vinegar

 

mix all up. Spritz the joining areas with vinegar prior to attaching. Smear the spooze on both pieces, attach. Hold for 30 seconds. Let dry. The area may need sanding, depending on how much spooze was slathered on and wehter it squirted out. Then bisque, or glaze if doing single fire.

 

I used this on a goblet that had dried too much before attaching the stem. Of course the goblet broke off at the join. Applied spooze and then handled the greenware goblet with gusto.  Pouring in/ out glaze for the liner then spraying glaze for a single fire. You cannot tell it was broke. 

[Stone Spiral]

Wow, cool! What a creative fix. I will let her know and we will give it a shot!

[Joseph Fireborn]

Also. After you attach the handle with the spooze solution, put it in plastic and give it a week to dry slowly. The moisture needs to absorb slowly into both sides the handle and the cup to avoid the cracks. It still might crack or fall off during the firing though! Good luck!

[Stone Spiral]

Oh, thank for that - seems like an important tip!

[preeta]

honestly so not worth the effort (unless lots of carving on the cup). she can easily pull off another cup and handle in the time she will use to fix everything. and this will be a second time around. 

 

just tell her to make another one. the second one always comes out better. more practice. this is a death defying activity. handle on the cup going against gravity. unless she props the handle against the cup.

 

she already learnt a huge lesson about drying from this cup anyways. 

[dhPotter]

The syrup makes the concoction very sticky. The handle will hold.

 

I had not heard that about drying slowly after using spooze. The goblet I used this on, I let open air dry overnight and glazed it the next day. I have also used this for a handle on a mug.

 

The 2 pieces MUST be bone dry. I tried fixing a mug when it was almost dry. The handle came off. Waited till bone dry and the handle stayed connected. 

[Denice]

I wouldn't fire it in my kiln the handle could fall off and stick to the shelf.    Denice

[dhPotter]

I have done 3 goblets and 1 mug handle. The join seems stronger then the clay itself. Try it.

 

Before I started single firing, some pieces were bisqued before glazing. Now that I am single firing 2 goblets were done like this and worked. In fact, after glazing the liner of a set of goblets, I realized 2 of them were the patched up ones. I was oblivious to any difference in handling.

 

I am sure one of our resident chemists could tell us why the vinegar is needed.

[Callie Beller Diesel]

Paper clay also works, and can adhere bone dry to bone dry, but I'd encourage her to remake the piece. A sculpture would be worth the repair, but I don't think a mug is.

[Sequoia Pottery]

This has been a while, if anyone is still paying attention to this:  Recently I ran across an old patent about attaching dry ceramic objects together, like a dry handle to a dry mug.  Now I can't find it!  Here is the process as I remember it.  (1)  "machine" the two objects to fit as closely as possible.  (2) Brush the two objects with a generous coating of 4% solution of polyvinyl alcohol and allow to sink in.  (3) mix a slurry of clay body with the 4% solution of pva, coat both objects to be joined, press them together, and ...voila.  

I routinely use polyvinyl alcohol on regular mug handles and it seems to work very well, but have never tried it dry.  Does anyone have experience with this?

[Min]

Interesting.

If you do try it for dry joining it would be nice to hear if it works. Do you get it from a chemical supply house online or ? 

Welcome to the forum 

[TabbyCat]

Hi!  I just tried this spooze method for some pieces I'm trying to join together and it did not hold at all.  What am I doing wrong?  Measured a third of each (1/4 cup)... it was very liquid and not thick like I had hoped. I'll plan to try again with more corn syrup but any ideas would be helpful.  Fyi I am not trying to fix a crack but actually attach two unrelated but flat pieces of bone dry porcelain. 

 

TIA!

[liambesaw]

23 minutes ago, TabbyCat said:

Hi!  I just tried this spooze method for some pieces I'm trying to join together and it did not hold at all.  What am I doing wrong?  Measured a third of each (1/4 cup)... it was very liquid and not thick like I had hoped. I'll plan to try again with more corn syrup but any ideas would be helpful.  Fyi I am not trying to fix a crack but actually attach two unrelated but flat pieces of bone dry porcelain. 

 

TIA!

Use paper clay slip, works much better for joining bone dry.  Probably still won't work, but will work better because it doesn't shrink much as it dries and it dries fast.

[Mark C.]

( old patent) does not mean it works

just patented 

polyvinyl alcohol is an odd product to use-its for paper and printing and fabrics.

Maybe its the cats meow and we just did not know it

are you a paper maker?

[liambesaw]

PVA is Elmer's glue, or am I thinking of a different PVA?  Polyvinyl acetate? 

Edit: looked it up, it's hydrolyzed Elmer's glue

[TabbyCat]

Thank you! I'll try the paperclay.  It's worked with just my slip but I'm hoping for something a little stronger! I'll post if i find something that works well. 

[Min]

17 hours ago, liambesaw said:

PVA is Elmer's glue, or am I thinking of a different PVA?  Polyvinyl acetate? 

Edit: looked it up, it's hydrolyzed Elmer's glue

I don't think it's the same thing. From Wiki, the polyvinyl alcohol is [CH2CH(OH)]n and the polyvinyl acetate is (C4H6O2)n. Apart from the paper products uses the polyvinyl alcohol is also used in eye drops and contact lenses solutions. Elmers glue maybe not so much  

[liambesaw]

10 minutes ago, Min said:

I don't think it's the same thing. From Wiki, the polyvinyl alcohol is [CH2CH(OH)]n and the polyvinyl acetate is (C4H6O2)n. Apart from the paper products uses the polyvinyl alcohol is also used in eye drops and contact lenses solutions. Elmers glue maybe not so much  

Yeah, it's actually made from Elmer's glue, it's the hydrolyzed version.  Glue + ethanol + heat I think is how it's made, just looking at the chemistry.  Pretty interesting!  Sounds like it's just as sticky as Elmer's glue too, which is pretty neat, but I don't know that it would make much difference in this application.  

[JohnnyK]

The main question here is "Will it hold up to firing?" I'm having problems with the handle joints cracking on a few large mugs that I've made and I think I'll try the paper slip route for reinforcing the joints. What would be the best formula for making the paper slip?

[liambesaw]

5 minutes ago, JohnnyK said:

The main question here is "Will it hold up to firing?" I'm having problems with the handle joints cracking on a few large mugs that I've made and I think I'll try the paper slip route for reinforcing the joints. What would be the best formula for making the paper slip?

I take some slip from the bottom of my throwing bucket, and just add shredded toilet paper until it thickens a bit.  I'd say for a cup of slip, about 5 sheets of 2-ply shredded up nicely and once the paper is hydrated I hit it with the immersion blender.  Turns into a thick paste and then I use that.

Don't know if it helps with cracked handle joints but it definitely will fill a crack in a piece.  

[Babs]

21 hours ago, JohnnyK said:

The main question here is "Will it hold up to firing?" I'm having problems with the handle joints cracking on a few large mugs that I've made and I think I'll try the paper slip route for reinforcing the joints. What would be the best formula for making the paper slip?

Maybe Magic water or just slip + vinegar at joining time. Backfilling around joint helps too. Mugs covered wih plastic for a little while to equalise the moisture depending on ambient humidity helps too.

[CactusPots]

Have you ever tried to pick up a bone dry pot by the rim and pulled a big chunk out of the rim?  Believe it or not, I have put that piece back in and fired to bisque and then to glaze and it can't be seen.  Paper clay is a really valuable tool.

[Benzine]

I used to use the "Spooze" mix, and will still do so on occasion.  What I've become partial to, is using a combination of magic water, and a super clay saturated, deflocculated slip.

I'll dab some magic water on the connection points, score the surface, more magic water,  a healthy dab of the slip, then just press the pieces together with a little side to side or twisting motion, and smooth everything out.

I will say that I usually have to go back a few times, and touch up any cracks that may have shown up. 

I've used it to fix many rim breaks, where *someone* picked the ware up incorrectly (Because of course, I never specifically told them not to, even telling them exactly what would happen, and what it would look like if they chose to ignore that advice)...  I've also added things on, right as I was loading them into the bisque (usually nothing structural, just small bits that weren't attached properly)

I honestly don't know if I have used this to repair a handle, as usually in that case, we rehydrate the ware, remove the old handle and make a new one.

A few years ago, I did a bit of an experiment, where I joined some uniform pieces together using a couple different joining materials/ processes, and at different stages of dryness (workable, leatherhard, bone dry).  I then tested how strong they were both before and after the bisque. 

I mainly did this to illustrate the importance of a proper join, done at the right time.  I'd have to go look to see what I found to be the best method, though I can say nothing at the bone dry stage was nearly as strong as those done earlier.  I might have to replicate that experiment!

[LeeU]

I know that Spooze & Magic Water are not the same thing. I looked at the recipe for the water, but I don't mix chemicals these days (no room to make clay/glaze/storage etc./low volume production). Is there any major-major diff 'tween the two for simple repairs (^6)? I love Spooze-it's never not worked for me.