If you paint en plein air with oils and find you mix the same colour often it might be useful to make a pre-mixed version and create your own tube of oil paint. You’ll save mixing time and may need to carry fewer tubes with you. Another reason you might need to fill oil paint tubes is of course if you grind your own oil paint, when you will probably want to put your handmade colours in tubes for airtight storage. Jackson’s easy-to-use empty paint tubes are perfect for both storing custom mixes and handmade paint.
Acrylic colour stays wet fine in a jam jar with a little water added or a sealed plastic container with a wet sponge inside. But oil colour will dry if even a little air is in the container, tins of artists oil colour often have a thick skin of dried paint inside. So putting oil paint in tubes makes sense, because you need to keep all the air out. Jackson’s stock empty paint tubes and I had never used them so was not sure how to fill them or close the tube securely. So we made some paint and we made some mixes and tried a few ways of filling and closing. It turned out to be pretty straightforward. If you have any helpful suggestions from your experience, please leave a comment below.
Making Custom Mixes
Useful for storing your special mixes in an airtight way, especially for taking plein air painting.
I wanted to make a general sky blue mixture that would be useful for a lot of paintings, only needing slight modification for each landscape. Debbie was painting a landscape and so she made a mix of sky blue to show what she needed for her painting and I matched it and made a lot to have a tube she could use for lots of paintings.
If you are trying to match a colour it helps to paint a bit on your palette and keep checking if you are heading in the right direction. If mixing a light colour it’s a good idea to start with the white and add the other colours to it, not the other way round. Many light colours like Sky Blue require a large proportion of white. This Sky Blue is 10 parts Titanium White to one part Phthalo Blue. If I had started with a huge pile of blue I would have needed 3 tubes of white and mixed way too much colour.
For another convenience tube I also mixed a warm, light, Sky Grey using mostly Titanium White with some Ultramarine Blue, Burnt Umber and a touch of Cadmium Red.
For putting your paint mix into a tube and crimping the tube securely, skip past the paint making section below to the filling and crimping section.
Making Your Own Paint
It is easier to grind your own oil paint than I remember from trying it in the past. I think the key is to have the right tools. A glass muller and a grinding slab will allow you to grind the pigment into the oil without too much effort, as they both have a bit of texture to them. Jackson’s stock three sizes of muller, but we do not stock any grinding slabs. Fortunately you can make your own without too much trouble. Using a thick piece of tempered glass (a replacement glass shelf from a flat-pack store is an economical choice, they are tempered for safety and have rounded edges for safety) you can give it tooth by having it sandblasted or in just 15 minutes you can grind a tooth onto it yourself with a muller and some grinding grit. Find some carborundum powder in medium grit (about 120), place some corrugated cardboard under your glass sheet to cushion it, on the glass mix a spoonful of the carborundum powder with water to a runny paste and using the muller grind in an even circular pattern over the entire surface using low to medium pressure for about 15 minutes. Wash the now frosted surface clean and your toothy grinding slab is ready to grind pigment into oil for paintmaking.
There are really only two ingredients to oil paint: a pigment and a drying oil (this is a vegetable oil that dries to a hard finish when exposed to air, like poppyseed, walnut, safflower, linseed). I started with a puddle of linseed oil, sprinkled pigment powder on and then ground it in. I kept adding more pigment until it was fairly pasty. The two colours we made, Terre Vert and Burnt Sienna, were softer than the ready-made oil paint I used for the custom mixes earlier. If I had kept adding pigment it might have been possible to make the paint stiffer. As I went along I stopped to scrape the plate and muller and pile the paint in the centre. I continued grinding this until it was piling up in thick ridges. Then I scraped that batch into the tube and made some more. We made too much Burnt Sienna, enough to completely fill the tube. I had to squeeze some out to leave room for folding the end of the tube over.
Experienced paint makers know about pigment drying times and oil characteristics and can match their choice of oil to pigment. A fast drying pigment like cobalt blue can be mixed with a slow drying oil like poppyseed to balance the drying time out with the rest of your colours and a slow drying pigment like ivory black can be mixed with a faster drying oil like linseed. In addition to the different drying times, some of the oils (poppyseed, walnut, safflower) also yellow less over time than the more popular linseed oil, so they are a good choice for lighter colours. There are also different types of linseed oil, created by different methods of processing (cold-pressed, refined, stand, etc.) that dry at different rates with different amounts of yellowing. There are other characteristics of the different oils that you may be interested in researching if you are making custom oil paints, like film durability and elasticity, that affect cracking and crazing.
You probably won’t save any money making your own tubes of oil colour as it takes a fair amount of pigment, and yours probably won’t be as smooth and buttery as triple-milled artists’ colours, but you can control characteristics of your paint. By making your own paint you can control the stiffness of the paint, choose the type of oil you use, you can add additional ingredients if you want like beeswax or siccatives (driers), and you can use a custom blend of pigments. Store-bought oil paint goes through an ageing process after the tubes are filled, that helps prevent separation in the tube, where you squeeze out clear oil instead of paint. I am not too familiar with this, but I understand they rotate the tubes top to bottom every few weeks during this time. I checked our two handmade paints after a week and there was no separation in the tube.
If you are making your own paint it is a great idea to keep a record of your process and your formulae, so you can learn from it. Also keep in mind that some pigments are toxic and that you don’t want to be breathing in any type of powder, so be sure to familiarise yourself with the pigment and also take appropriate safety measures for working with powders.
Filling the Empty Paint Tubes
Jackson’s empty paint tubes are easy to use and have nice screw caps that fit well. The 60ml tube is a good versatile size, fill it only halfway if you only need a smaller size. The 60ml volume is based on allowing the bottom to be folded over a few times. They come singly or in packs of 10. Each soft aluminium tube has an epoxy coating on the inside to prevent any corrosion.
For the custom mixes I scraped the paint into the open end of the tube with a palette knife as soon as it was the right colour. I then tapped the closed end sharply on the table to get the paint to settle to the bottom. For the handmade paint, as each batch of paint was thick enough I scooped it up with a palette knife and scraped it into an empty tube. I then ground more paint and continued filling until the tube was no more than 3/4 full or I had as much as I needed. Some of the tubes were only 1/2 full, as that is all the paint I made. I had a toilet roll on hand for wiping things and used it on its end as a stand, the cardboard centre was handy for holding the half-filled tube upright. But it turns out the paint was probably thick enough for the tube to be left on its side as I ground the next bit. With tapping on the table the softer handmade paint settled more easily down to the cap end of the tube than the sticky readymade paint, I had to do a bit more squeezing and scraping with those.
My biggest concern was filling the tube with no air. Scraping it in, knocking it to get it all down to the cap end and squeezing it closed from the paint towards the end (not the end towards the paint) seemed to work well. I tried using the plunger from a syringe that was a close size, but not too tight a fit so that air was able to escape past the sides and wasn’t pushed down to be trapped. But so much of the paint stuck to the plunger that it seemed a waste of paint and didn’t seem to improve the situation anyway. It was also hard to clean. I had another thought but didn’t try it: we have a slightly smaller syringe that could squeeze the paint deeper into the empty tube but it seemed that if you were filling the syringe full of paint you might as well just use it from the syringe. I think historically watercolours came in a syringe centuries ago. Another option that would work would be filling a disposable plastic pastry bag, snipping the end off and piping the paint into the tube. But I’m not sure it would reduce any mess or prevent any trapped air any more than filling with a palette knife and tapping the paint down and of course some paint would be wasted inside the bag. In the end, the simplest method seemed to work the best – scraping it in with a palette knife.
Crimping the Empty Paint Tubes
My second concern with the tubes was crimping them well enough that when you use it later you won’t squeeze the tube and have the back unfold.
The aluminium is really soft and easy to fold. The only tools I used were a metal ruler and a pair of pliers.
To keep it airtight I pinched the tube at the point where the paint stopped and then flattened the tube away from there. Then using the metal ruler I folded a few mm of the tube over and squeezed it flat with the ruler or the pliers. I repeated this for 3 folds. For the less filled tubes I folded more just to use up the tube, but from testing for squeezing pressure it is the three folds that matter for sealing. For partially filled tubes you could probably cut the tube down, it is very soft, but I didn’t do this I just folded it more. Then I gave a final crimp to the closure with the pliers – these can be any pliers including canvas stretching pliers. My folds got neater with practice.
I also tried using the tube wringer that I had to hand (a useful tool for the studio, it lets you get the last bit of paint from your tubes). It worked as well as the ruler and pliers and did just as well in the squash test.
To see if store-bought tubes were glued or welded or something I opened one up. Each manufacturer is probably different but this one was just folded and flattened. To see how much pressure a store-bought tube could take I put most of my weight on a closed tube on a table and it unfolded just a bit of the last fold but no more. I think it would need some serious stamping or crushing to pop the back open. I did the same squashing test on the handmade tubes and had the same results. So this method of folding and pinching seems to be just as effective as commercial methods. But, in any case, I would just be aware when squeezing out paint to use, you should squeeze towards the cap end!
It might be possible to recycle a finished paint tube by opening it up and filling it with a custom mixture or decanting paint from a larger size and then crimping it shut again. I didn’t try this, so am not sure how easy it is to open up a used-up tube. If anyone has tried this, please leave a comment, I’d be really interested to know if this works.
Click on the underlined link to go to the current offer on the Empty Aluminium Tubes to fill with your own oil paint on the Jackson’s Art Supplies website.